記述言語：英語  

DOI： 10.1557/s43577-025-00997-6

Web of Science

researchmap

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.actamat.2025.121315

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsaem.5c01558

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/adf7b2

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/adf4f0

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsaelm.5c00262

Web of Science

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/adefe9

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.25014

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.25009

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsaelm.5c00556

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/adma.202511001

Web of Science

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2506.14452v1

Ferroelectric polarization switching underpins the functional performance of
a wide range of materials and devices, yet its dependence on complex local
microstructural features renders systematic exploration by manual or grid-based
spectroscopic measurements impractical. Here, we introduce a multi-objective
kernel-learning workflow that infers the microstructural rules governing
switching behavior directly from high-resolution imaging data. Applied to
automated piezoresponse force microscopy (PFM) experiments, our framework
efficiently identifies the key relationships between domain-wall configurations
and local switching kinetics, revealing how specific wall geometries and defect
distributions modulate polarization reversal. Post-experiment analysis projects
abstract reward functions, such as switching ease and domain symmetry, onto
physically interpretable descriptors including domain configuration and
proximity to boundaries. This enables not only high-throughput active learning,
but also mechanistic insight into the microstructural control of switching
phenomena. While demonstrated for ferroelectric domain switching, our approach
provides a powerful, generalizable tool for navigating complex,
non-differentiable design spaces, from structure-property correlations in
molecular discovery to combinatorial optimization across diverse imaging
modalities.

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2506.08073v1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsami.5c14008

Web of Science

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2505.24062v1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0268889

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/d5dd00119f

Web of Science

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2504.20011v2

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0261572

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/admi.202400627

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/adb46c

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/aelm.202400880

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0233070

Web of Science

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2408.00229v1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/adfm.202409240

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.25011

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0236507

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/d4dd00299g

Web of Science

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2409.12295v1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsnano.4c05368

Web of Science

PubMed

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2404.12899v1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/ad6fa9

Web of Science

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ad6fa9/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/d4dd00277f

Web of Science

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2408.02071v1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsaelm.4c00368

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0202063

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.23207

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.23210

Web of Science

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society (ACS)  

DOI： 10.1021/acsanm.3c04636

researchmap

掲載種別：研究論文（学術雑誌）  

The current focus in Autonomous Experimentation (AE) is on developing robust
workflows to conduct the AE effectively. This entails the need for well-defined
approaches to guide the AE process, including strategies for hyperparameter
tuning and high-level human interventions within the workflow loop. This paper
presents a comprehensive analysis of the influence of initial experimental
conditions and in-loop interventions on the learning dynamics of Deep Kernel
Learning (DKL) within the realm of AE in Scanning Probe Microscopy. We explore
the concept of 'seed effect', where the initial experiment setup has a
substantial impact on the subsequent learning trajectory. Additionally, we
introduce an approach of the seed point interventions in AE allowing the
operator to influence the exploration process. Using a dataset from
Piezoresponse Force Microscopy (PFM) on PbTiO3 thin films, we illustrate the
impact of the 'seed effect' and in-loop seed interventions on the effectiveness
of DKL in predicting material properties. The study highlights the importance
of initial choices and adaptive interventions in optimizing learning rates and
enhancing the efficiency of automated material characterization. This work
offers valuable insights into designing more robust and effective AE workflows
in microscopy with potential applications across various characterization
techniques. The analysis code that supports the funding is publicly available
at https://github.com/Slautin/2024_Seed_effect_DKL_BO.

DOI： 10.1063/5.0198316

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2402.00071v2

掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society (ACS)  

DOI： 10.1021/acsaelm.4c00134

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/ad3a71

Web of Science

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.actamat.2024.119688

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society (ACS)  

DOI： 10.1021/acs.cgd.3c01367

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0180449

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Tetragonal (1-x)(Bi,Na)TiO3-xBaTiO3 films exhibit enhanced piezoelectric properties due to domain switching over a wide composition range. These properties were observed over a significantly wider composition range than the morphotropic phase boundary (MPB), which typically has a limited composition range of 1-2%. The polarization axis was found to be along the in-plane direction for the tetragonal composition range x = 0.06-1.0, attributed to the tensile thermal strain from the substrate during cooling after the film formation. A "two-step increase" in remanent polarization against an applied maximum electric field was observed at the high-field region due to the domain switching, and a very high piezoelectric response (effective d33 value, denoted as d33,f) over 220 pm/V was achieved for a wide composition range of x = 0.2-0.5 with high tetragonality, exceeding previously reported values for bulk ceramics. Moreover, a transverse piezoelectric coefficient, e31,f, of 19 C/m2 measured using a cantilever structure was obtained for a composition range of at least 10 atom % (for both x = 0.2 and 0.3). This value is the highest reported for Pb-free piezoelectric thin films and is comparable to the best data for Pb-based thin films. Reversible domain switching eliminates the need for conventional MPB compositions, allowing an improvement in the piezoelectric properties over a wider composition range. This strategy could provide a guideline for the development of environmentally acceptable lead-free piezoelectric films with composition-insensitive piezoelectric performance to replace Pb-based materials with MPB composition, such as PZT.

DOI： 10.1021/acsami.3c13302

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/D4RA02296C

Web of Science

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/IMFEDK64776.2024.10814248

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/UFFC-JS60046.2024.10793582

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/UFFC-JS60046.2024.10794165

Web of Science

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

Epitaxial (Bi, K)TiO3 films with 800- to 900-nm thicknesses were grown hydrothermally at 200 °C on SrTiO3 substrates covered with SrRuO3 layers. Perfectly (001)-oriented films grew on (100)SrTiO3 due to good lattice matching. Films on (110)SrTiO3 had mixed orientations of dominant (110) and minor (101), while three types of (111) orientations with in-plane 120° rotation were observed for the film on (111)SrTiO3. The (101) and (110) orientations of the film deposited on (110)SrTiO3 were tilted by approximately 2.6° and 1.6°, respectively, from surface normal due to the formation of a 90° domain with a twinning plane. The plane-view measurement for the film deposited on (111)SrTiO3 showed nine spots. These are explained by the presence of 15 possible spots resulting from the relaxed 90° domain combination and by overlapping. The lattice parameters of these films explain the tilting angles of these domains. These results reveal the formation of perfectly relaxed 90° domain structures for films grown on (110) and (111)SrTiO3. This differs from our previous data for tetragonal Pb(Zr,Ti)O3 films grown above TC on (110) and (111)SrTiO3 because the present films directly grow the ferroelectric films below TC without phase change. The tilting angle of the polar-axis and the volume fraction of the 90° domain can explain the piezoelectric responses of these films assuming that films have purely an up-state. This suggests that these films show almost pure up-state polarization without 180° domains, at least along surface-normal directions. These data show that these films have domain structures different from the well-known ones for the tetragonal Pb(Zr,Ti)O3 films.

DOI： 10.1063/5.0176337

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Recent progress in two-dimensional ferroelectrics greatly expands the versatility and tunability in van der Waals heterostructure based electronics. However, the switching endurance issue that widely plagues conventional ferroelectrics in practical applications is hitherto unexplored for van der Waals layered ferroelectrics. Herein, we report the observation of unusual polarization fatigue behaviors in van der Waals layered CuInP2S6, which also possesses finite ionic conductivity at room temperature. The strong intertwinement of the short-range polarization switching and long-range ionic movement in conjunction with the van der Waals layered structure gives rise to unique morphological and polarization evolutions under repetitive electric cycles. With the help of concerted chemical, structural, lattice vibrational and dielectric analyses, we unravel the critical role of the synergy of ionic migration and surface oxidation on the anomalous polarization enhancement and the eventual polarization degradation. This work provides a general insight into the polarization fatigue characteristics in ionically-active van der Waals ferroelectrics and delivers potential solutions for the realization of fatigue-free capacitors.

DOI： 10.1038/s41467-023-44132-y

PubMed

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

Ferroelectric (Al, Sc)N thin films have the potential for use in low-power memory applications. This study demonstrates the thickness scalability of ferroelectricity down to an approximately 20 nm-thick (Al0.8Sc0.2)N film sandwiched between microfabricable TiN electrodes. The impact of the deposition gas atmosphere during the sputtering process and the top electrode materials on the crystal structures and ferroelectric properties was investigated for 20–30 nm-thick (Al0.8Sc0.2)N thin films deposited on Si substrates covered with a TiN layer by radio frequency magnetron sputtering. The deposition atmosphere did not strongly affect the crystal structures of the 30 nm-thick (Al0.8Sc0.2)N films but significantly affected their ferroelectric properties. The leakage current density decreased for films deposited under pure N2 gas compared to the films deposited under a gas mixture of 0.67Ar + 0.33N2. The ferroelectric properties of 20 nm-thick (Al0.8Sc0.2)N films were changed by the top electrode materials; both the switching electric field and its maximum applicable electric field increased for the TiN top electrodes compared with the Pt top electrodes, improving the saturation characteristics of the remnant polarization (Pr) against the applied electric field. Consequently, the 20 nm-thick (Al0.8Sc0.2)N film sandwiched between the microfabricable TiN top and bottom electrodes showed ferroelectricity without noticeable degradation with decreasing film thickness; the film maintained large Pr values of over 100 μC/cm2 in the temperature range from room temperature to 150 °C. The present data open the door to scalable ferroelectric random-access memories using almost thickness-degradation-free thin (Al, Sc)N films with microfabricable TiN electrodes.

DOI： 10.1063/5.0166288

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: This study aimed to investigate the association between proteinuria and long-term prognosis in patients with coronary artery disease. METHODS: This was a single-center observational study. A total of 1351 patients were identified who underwent percutaneous coronary intervention, and whose urine data were available. Patients were divided into two groups according to the presence (n = 245) or absence (n = 1106) of proteinuria. All-cause and cardiovascular deaths were primarily evaluated. RESULTS: The prevalence rates of hypertension and diabetes were significantly higher, and the baseline estimated glomerular filtration rate (eGFR) was lower in patients with proteinuria than in those without proteinuria. During the median follow-up of 4.1 years (interquartile range, 1.7-6.8 years), the occurrences of all-cause and cardiovascular deaths were significantly higher in patients with proteinuria. Multivariable Cox regression analysis indicated that the presence of proteinuria was a significant predictor of cardiovascular death as well as age, BMI, reduced eGFR, and left ventricular ejection fraction. When stratified into four groups based on eGFR category (eGFR <60 or ≥60 ml/min/1.73 m2) and absence or presence of proteinuria, the incidence rates of all-cause and cardiovascular deaths were highest in patients with proteinuria and eGFR less than 60 ml/min/1.73 m2. Furthermore, the incidence rates of all-cause and cardiovascular deaths were significantly higher in patients with proteinuria among both diabetic and nondiabetic patients. CONCLUSION: Proteinuria is associated with the long-term prognosis, and all-cause and cardiovascular deaths in patients with coronary artery disease, regardless of eGFR and the presence or absence of diabetes mellitus.

DOI： 10.2459/JCM.0000000000001573

PubMed

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

In this study, the switching kinetics in a (001)-out-of-plane-oriented (Al0.8Sc0.2)N thin film were systematically investigated as a function of temperature and frequency. The switching behavior followed the Kolmogorov–Avrami–Ishibashi model within the temperature and write-pulse width ranges of 300–473 K and 10 Hz–600 kHz, respectively. The switching speed increased linearly with the electric field, even at high electric fields. The frequency dependence of the coercive field (Ec) evaluated at room temperature revealed that the scaling regime of the domain-wall propagation did not transition to the flow regime, and the switching velocity of the domain increased linearly with the electric field even at high frequencies up to 600 kHz. The invariant domain-wall motion regime implies the potential of using (Al,Sc)N films for high-frequency applications. In addition, a formula for estimating the coercive field of an (Al,Sc)N film was derived by fitting the parameters obtained from the study of switching behavior. The formula indicated that the switching electric field tends to become insensitive to frequency as temperature increases. Moreover, the frequency dependency of the field was minimal even at room temperature. This is a useful index for estimating the drive voltage at the operating frequency and temperature.

DOI： 10.1063/5.0171108

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/ace3ce

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/ace330

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

AIM: The relationship between carotid artery ultrasound findings and clinical outcomes in patients who undergo percutaneous coronary intervention (PCI) has not been completely elucidated. METHODS: This single-center retrospective study investigated 691 patients who underwent PCI and carotid ultrasound testing. Maximum carotid intima-media thickness (CIMT) was defined as the greatest CIMT at the maximally thick point among the common carotid artery, carotid bulb, and internal carotid artery. A carotid plaque was defined as vessel wall thickening with a CIMT ≥ 1.5 mm. The characteristics of carotid plaque (heterogeneity, calcification, or irregular/ulcerated surface) were evaluated visually. Patients were divided into those with and without heterogeneous carotid plaque (maximum CIMT ≥ 1.5 mm and heterogeneous texture). The endpoint was the incidence of a major adverse cardiovascular event (MACE) defined as a composite of cardiovascular (CV) death, myocardial infarction, and ischemic stroke. RESULTS: Among 691 patients, 309 were categorized as having a heterogeneous plaque. Patients with heterogeneous plaques were at a higher risk of MACE than those without (p=0.002). A heterogeneous plaque was independently associated with MACE after adjusting for covariates (hazard ratio [HR], 1.71; 95% confidence interval [CI], 1.01-2.90; p=0.046). Calcified or irregular/ulcerated plaques were correlated with a higher incidence of MACE, but both were not independently associated with MACE (HR, 1.35; 95% CI, 0.69-2.64, p=0.38 and HR, 0.98; 95% CI, 0.57-1.69; p=0.95, respectively). CONCLUSION: The presence of a heterogeneous carotid plaque in patients who underwent PCI predicted future CV events. These patients may require more aggressive medical therapy and careful follow-up.

DOI： 10.5551/jat.63622

PubMed

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

Ferroelectric hafnium and zirconium oxides have undergone rapid scientific development over the last decade, pushing them to the forefront of ultralow-power electronic systems. Maximizing the potential application in memory devices or supercapacitors of these materials requires a combined effort by the scientific community to address technical limitations, which still hinder their application. Besides their favorable intrinsic material properties, HfO2–ZrO2 materials face challenges regarding their endurance, retention, wake-up effect, and high switching voltages. In this Roadmap, we intend to combine the expertise of chemistry, physics, material, and device engineers from leading experts in the ferroelectrics research community to set the direction of travel for these binary ferroelectric oxides. Here, we present a comprehensive overview of the current state of the art and offer readers an informed perspective of where this field is heading, what challenges need to be addressed, and possible applications and prospects for further development.

DOI： 10.1063/5.0148068

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：Ceramic Society of Japan  

DOI： 10.2109/jcersj2.22154

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1002/pssa.202300100

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsaem.3c00577

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsaelm.2c01658

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.sna.2023.114265

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

Abstract

The dependence of the output power of piezoelectric vibration energy harvesters on film thickness was systematically investigated using {100}c-oriented epitaxial (K,Na)NbO₃ films prepared on single-crystal SrTiO₃ substrates by the hydrothermal deposition technique. First, we measured the vibration energy harvesting properties by a unimorph Pt/(K,Na)NbO₃//SrRuO₃//SrTiO₃ cantilever. Based on the fact that the elastic stiffness of (K,Na)NbO₃ is lower than that of SrTiO₃ substrate, it can be understood that increasing film thickness leads to decreasing Qm, resulting in the decrease in output power as film thickness increased under the same input acceleration condition. In the next step, these cantilevers were attached to an Al plate having a much larger volume than the Pt/(K,Na)NbO₃//SrRuO₃//SrTiO₃ cantilever. The output power of this type of harvester was more than 400% greater when the film thickness was increased from 3.5 μm to 22.3 μm due to the almost constant Q_m value.

DOI： 10.35848/1347-4065/acaa79

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/acaa79/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: This study aimed to evaluate the correlation and diagnostic agreement between diastolic pressure ratio (dPR) and fractional flow reserve (FFR) in a Japanese real-world setting. DESIGN: Prospective multicenter observational study. METHODS: This study included 100 patients with intermediate coronary artery stenosis at 4 Japanese hospitals. For these lesions, FFR and dPR were measured using a guidewire with a sensor and a monitor to measure intravascular pressure. The correlation and diagnostic agreement between FFR and dPR were assessed. When both FFR and dPR were negative or positive, the results were considered to be concordant. When one was positive and the other was negative, the result was regarded as discordant (positive discordance, FFR > 0.80 and dPR ≤ 0.89; negative discordance, FFR ≤ 0.80 and dPR > 0.89). RESULTS: Overall, the FFR and dPR were well-correlated (R = 0.841). FFR and dPR were concordant in 89% of cases (concordant normal, 43%; concordant abnormal, 46%) and discordant in 11% (positive discordance, 7%; negative discordance, 4%). No significant difference was observed in the rate of concordant results between patients with and without diabetes mellitus. The diagnostic concordance rate was significantly different among the 3 coronary arteries (right coronary artery, 93.3%; left anterior descending artery, 93.2%; and left circumflex artery, 58.3%; P = .001). Additionally, the rate of concordant results tended to be higher when using intravenous administration of adenosine than when using intracoronary bolus injection of nicorandil (adenosine, 95.1%; nicorandil, 84.7%; P = .103). CONCLUSION: We found that dPR was highly correlated with FFR, and diagnostic discordance was observed in 11% of the lesions. Several factors, including lesion location and medication for hyperemia, may cause the diagnostic discordance between dPR and FFR.

DOI： 10.1097/MD.0000000000032578

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

In this study, the ferroelectric phase of PbTiO₃ (PTO) thin films was grown on cubic single-crystal KTaO₃ (KTO) substrates using metal–organic chemical vapor deposition. X-ray diffraction (XRD) was used to reveal an a₁ /a₂ domain structure, which remained unchanged down to a film thickness of 2 nm. The a₁ and a₂ polydomains do not have a simple tetragonal symmetry because a_a∥ and a_a⊥ do not have the same values. The crystallographic tilt angle, α, is defined based on the rotation angle of the PTO lattice with respect to the cubic phase of KTO substrates. The in-plane tetragonal distortion ( c_a∥/ a_a∥) and α decreased with the decrease in the film thickness, following the in-plane tetragonal geometric equation: [Formula: see text]. The isotropic tensile strains induced in-plane polarization directions along the [100] and [010] axes of the substrates. These axes are formed via the a₁/ a₂ polydomain of the tetragonal-like phase. Moreover, synchrotron in-plane grazing incidence XRD and piezoelectric force microscopy were used to reveal the thickness dependency of the periodic domain width of the ferroelastic a₁/ a₂ domain. The periodic domain width in the PTO films decreased, following Kittel's law, with the reduction in the film thickness.

DOI： 10.1063/5.0119843

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Epitaxial layers of ferroelectric orthorhombic HfO2 are frequently investigated as model systems for industrially more relevant polycrystalline films. The recent success in stabilizing the orthorhombic phase in the solid-solution cerium oxide - hafnium oxide system allows detailed investigations of external influences during fabrication. This report analyzes the ferroelectric properties of two thin film capacitors, which were post-deposition annealed in N2 and O2 atmospheres to achieve the orthorhombic phase after room temperature deposition. The samples, which exhibit very similar constituent phase, appear identical in conventional polarization-field hysteresis measurements. However, a significant switching speed difference is observed in pristine devices. Continued field cycling reduces the difference. Deeper analysis of switching transients based on the Nucleation Limited Switching model suggests that the O2 heat treatment atmosphere results in an altered oxygen vacancy profile, which is reverted during ferroelectric cycling.

DOI： 10.1186/s40580-022-00344-4

PubMed

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society (ACS)  

DOI： 10.1021/acsaelm.2c00999

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

Abstract

The composition dependence of ferroelectric properties was investigated for (111)-oriented epitaxial HfO₂-CeO₂ solid solution films. Twenty-nanometer-thick films with different compositions were prepared on (111)ITO//(111)YSZ substrates at room temperature by pulsed laser deposition and subsequent heat treatment at 1000 oC under atmospheric N₂ and O₂ flows. All of the films had fluorite structures, and their crystal symmetries changed from monoclinic to tetragonal/cubic through orthorhombic phases as the (Hf_1-xCe_x)O₂ (x =0.12-0.25) increased in the film. The orthorhombic phase was confirmed for films with x = 0.15 and 0.17. On the other hand, ferroelectric properties were observed in films with x = 0.15-0.20, suggesting that a field-induced phase transition for films with x = 0.20. The film composition showing ferroelectricity was the widest for the reported epitaxial HfO₂-based films. Their remanent polarization (P_r) and coercive field (E_c) were almost the same, at 17-19 μC/cm² and 2.0-3.0 MV/cm, respectively. This wide ferroelectric composition range with relatively similar ferroelectricity is due to the solid solution of the same fluorite structure of HfO₂ and CeO₂ with monoclinic and cubic symmetries, that is respectively lower and higher crystal symmetries of the ferroelectric orthorhombic phase.

DOI： 10.35848/1347-4065/ac80e9

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac80e9/pdf

掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

Abstract

The asymmetry in the capacitance–voltage (C–V) curves obtained from a ferroelectric material can provide information concerning the internal microstructure of a specimen. The present study visualized nanoscale switching of a HfO₂-based ferroelectric thin film in real space based on assessing asymmetry using a local C–V mapping method. Several parameters were extracted from the local C–V curves at each point. The parameter V_i, indicating the lateral shift of the local C–V curve, was employed as an indicator of local imprint. In addition, the differences in the areas between the C–V curves for the forward and reverse sweeps, S_f − S_r, provided another slightly different indicator of nanoscale switching asymmetry. These parameters obtained from asymmetric C–V curves are thought to be related to internal electric fields and local stress caused by defects in the film. The work reported here also involved a cluster analysis of the extracted parameters using the k-means method.

DOI： 10.35848/1347-4065/ac7f7a

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac7f7a/pdf

掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

Abstract

Two types of vibrators using hydrothermally synthesized ferroelectric (K, Na)NbO₃ films were fabricated on SrTiO₃ substrates. Cantilever piezoelectric vibrators with film thicknesses of 3.5–22.3 μm were used under low-frequency and no resonance drive. The obtained output displacement increased almost linearly as the film thickness increased under both unipolar and bipolar drives. The obtained transverse piezoelectric coefficient, e_31,f, was almost independent of film thickness, ≈−5 C m⁻². On the other hand, a longitudinal piezoelectric vibrator was used under the resonance of half-length longitudinal vibration. The electromechanical coupling factor, k_eff², and the mechanical quality factor, Q_m, were evaluated. k_eff² and Q_m respectively increased from 0.14% to 1.23% and decreased from 556 to 224 as the film thickness increased from 2.5 to 26 μm. By applying a large voltage of 50 V_0-p, a large vibration velocity of 1.5 m s⁻¹ was obtained for the vibrator with a film thickness of 26 μm.

DOI： 10.35848/1347-4065/ac8046

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac8046/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Piezoresponse force microscopy (PFM) is widely used for characterization and exploration of the nanoscale properties of ferroelectrics. However, quantification of the PFM signal is challenging due to the convolution of various extrinsic and intrinsic contributions. Although quantification of the PFM amplitude signal has received considerable attention, quantification of the PFM phase signal has not been addressed. A properly calibrated PFM phase signal can provide valuable information on the sign of the local piezoelectric coefficient-an important and nontrivial issue for emerging ferroelectrics. In this work, two complementary methodologies to calibrate the PFM phase signal are discussed. The first approach is based on using a standard reference sample with well-known independently measured piezoelectric coefficients, while the second approach exploits the electrostatic sample-cantilever interactions to determine the parasitic phase offset. Application of these methodologies to studies of the piezoelectric behavior in ferroelectric HfO2 -based thin-film capacitors reveals intriguing variations in the sign of the longitudinal piezoelectric coefficient, d33,eff . It is shown that the piezoelectric properties of the HfO2 -based capacitors are inherently sensitive to their thickness, electrodes, as well as deposition methods, and can exhibit wide variations including a d33,eff sign change within a single device.

DOI： 10.1002/adma.202206237

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Ferroelectric thin films are important because of their great potential for use in various electric devices such as ferroelectric random-access memory. It was expected that Bi2SiO5, a Si-containing ferroelectric material, would show improved ferroelectricity by targeting a film with the (001)-orientation (polar-axis) on the substrate. Although there was a narrow process window for the deposition of the (010)/(001)-oriented Bi2SiO5 thin film, it was successfully prepared on a (101)-oriented TiO2 single substrate using the pulsed layer deposition technique. The optimum film deposition conditions and film thickness were found, and in this material, the volume fraction of the (001)-oriented domain reached about 70%. By controlling film orientation to the polar axis, the remanent polarization value of this film was 4.8 μC cm-2, which is the highest value among reported Bi2SiO5.

DOI： 10.1038/s41598-022-19058-y

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/ac819a

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society (ACS)  

Pressure-induced phase transitions in a monoclinically distorted LiNbO3-type CuNbO3 with triangularly coordinated Cu and octahedrally coordinated Nb were experimentally and computationally investigated. Phase transitions into GdFeO3-type or NaIO3-type structures generally observed in LiNbO3-type compounds below 30 GPa were not detected in CuNbO3 even at the maximum experimental pressure, 32.4 GPa. Our density functional theory calculations revealed that the phase transition is suppressed by the preference for the CuO3 triangular coordination environment, which reduces the total internal energy. This study clarifies that the change in the coordination environment of given ions can affect the pressure-induced phase transition.

DOI： 10.1021/acs.inorgchem.2c01766

PubMed

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1882-0786/ac8048

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：Ceramic Society of Japan  

DOI： 10.2109/jcersj2.22029

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Oxford University Press ({OUP})  

DOI： 10.1017/s1431927622010972

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s10853-022-07484-2

researchmap

その他リンク： https://link.springer.com/article/10.1007/s10853-022-07484-2/fulltext.html

We report the development and experimental implementation of the automated
experiment workflows for the identification of the best predictive channel for
a phenomenon of interest in spectroscopic measurements. The approach is based
on the combination of ensembled deep kernel learning for probabilistic
predictions and a basic reinforcement learning policy for channel selection. It
allows the identification of which of the available observational channels,
sampled sequentially, are most predictive of selected behaviors, and hence have
the strongest correlations. We implement this approach for multimodal imaging
in Piezoresponse Force Microscopy (PFM), with the behaviors of interest
manifesting in piezoresponse spectroscopy. We illustrate the best predictive
channel for polarization-voltage hysteresis loop and frequency-voltage
hysteresis loop areas is amplitude in the model samples. The same workflow and
code are universal and applicable for any multimodal imaging and local
characterization methods.

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2207.03039v2

掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

In this study, the bulk and surface acoustic waves (BAW and SAW) propagation properties of (K,Na)NbO₃ (KNN) films deposited by hydrothermal synthesis or RF magnetron sputtering methods were evaluated to investigate the applicability of such films to high-frequency devices. For the {100}_c-oriented KNN epitaxial films deposited by the hydrothermal synthesis method, a BAW phase velocity of 6900 m s⁻¹ and an electromechanical coupling coefficient k_t² of 8.4% were obtained. From the measured Rayleigh-type SAW properties, a large electromechanical coupling coefficient K² of 4.0% in the 1st mode was obtained in the {110}_c-oriented KNN epitaxial films. On the other hand, for the preferentially {100}_c-oriented KNN film deposited on Pt(111) by RF magnetron sputtering, a BAW phase velocity of 7850 m s⁻¹ and k_t² of 7.4% were obtained. For the 0th mode of the Rayleigh-type SAW, a propagation loss of 0.13 dB/λ (λ: wavelength) at 440 MHz and a temperature coefficient of frequency of –42 ppm °C⁻¹ were obtained for the {100}_c-oriented KNN epitaxial film deposited on STO(100) by the RF magnetron sputtering method.

DOI： 10.35848/1347-4065/ac4db9

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac4db9/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：特定非営利活動法人 超音波エレクトロニクス協会  

DOI： 10.35848/1347-4065/ac5722

CiNii Research

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Ceramic Society of Japan  

DOI： 10.2109/jcersj2.22002

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：Ceramic Society of Japan  

DOI： 10.2109/jcersj2.21184

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We develop and implement an automated experiment in multimodal imaging to
probe structural, chemical, and functional behaviors in complex materials and
elucidate the dominant physical mechanisms that control device function. Here
the emergence of non-linear electromechanical responses in piezoresponse force
microscopy (PFM) is explored. Non-linear responses in PFM can originate from
multiple mechanisms, including intrinsic material responses often controlled by
domain structure, surface topography that affects the mechanical phenomena at
the tip-surface junction, and, potentially, the presence of surface
contaminants. Using an automated experiment to probe the origins of non-linear
behavior in model ferroelectric lead titanate (PTO) and ferroelectric
Al0.93B0.07N films, it was found that PTO showed asymmetric nonlinear behavior
across a/c domain walls and a broadened high nonlinear response region around
c/c domain walls. In contrast, for Al0.93B0.07N, well-poled regions showed high
linear piezoelectric responses paired with low non-linear responses and regions
that were multidomain indicated low linear responses and high nonlinear
responses. We show that formulating dissimilar exploration strategies in deep
kernel learning as alternative hypotheses allows for establishing the
preponderant physical mechanisms behind the non-linear behaviors, suggesting
that this approach automated experiments can potentially discern between
competing physical mechanisms. This technique can also be extended to electron,
probe, and chemical imaging.

DOI： 10.1002/smll.202204130

PubMed

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2206.15110v1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The functionality of ferroelastic domain walls in ferroelectric materials is
explored in real-time via the in-situ implementation of computer vision
algorithms in scanning probe microscopy (SPM) experiment. The robust deep
convolutional neural network (DCNN) is implemented based on a deep residual
learning framework (Res) and holistically-nested edge detection (Hed), and
ensembled to minimize the out-of-distribution drift effects. The DCNN is
implemented for real-time operations on SPM, converting the data stream into
the semantically segmented image of domain walls and the corresponding
uncertainty. We further demonstrate the pre-selected experimental workflows on
thus discovered domain walls, and report alternating high- and low-
polarization dynamic (out-of-plane) ferroelastic domain walls in a (PbTiO3) PTO
thin film and high polarization dynamic (out-of-plane) at short ferroelastic
walls (compared with long ferroelastic walls) in a lead zirconate titanate
(PZT) thin film. This work establishes the framework for real-time DCNN
analysis of data streams in scanning probe and other microscopies and
highlights the role of out-of-distribution effects and strategies to ameliorate
them in real time analytics.

DOI： 10.1002/advs.202203957

PubMed

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2206.11457v1

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：{AIP} Publishing  

Scaling up the film thickness of HfO₂-based ferroelectrics is an important factor leading to their potential application in piezoelectric devices. In this paper, we report the ferroelectric and piezoelectric properties of 100 nm-thick 0.1CeO₂-0.9HfO₂ films, epitaxially grown on (001) indium-tin-oxide//(001)yttria-stabilized zirconia substrates. The crystal structure was investigated using x-ray diffraction and scanning transmission electron microscopy (STEM). These analyses revealed that the polar orthorhombic phase was stabilized, even at a thickness of 100 nm, whereas the formation of a nonpolar monoclinic phase was suppressed. In addition, the elemental mappings obtained by STEM–energy dispersive x-ray spectroscopy revealed that the film was compositionally uniform across its thickness. The chemical state of Ce in the polar orthorhombic domain was investigated using STEM–electron energy loss spectroscopy, which revealed the coexistence of Ce⁴⁺ and Ce³⁺. In addition, pinched polarization-electric field loops were observed, and their shapes were found to remain unaltered even after 10⁹ electric field cycles. The strain-electric field curves originating from ferroelectricity were observed before and after the electric field cycling, and the high-field observed strain, S_max/ E_max, was found to be approximately 7.2 pm/V. These results demonstrate that thicker CeO₂-HfO₂ ferroelectric films are promising candidates for use as piezoelectric materials.

DOI： 10.1063/5.0088491

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

Tetragonal (00l)-oriented epitaxial (Bi,K)TiO₃ films were grown at 240 °C on (100) _cSrRuO₃//(100)SrTiO₃ substrates by the hydrothermal method. KOH aqueous solutions and Bi(NO₃)₃ · 5H₂O and TiO₂ powders were used as the starting materials. Film thickness was controlled from 33 to 1200 nm by changing the deposition time, and the Bi/(Bi+K) ratio in the A-site of perovskite ABO₃ was almost constant for all film thicknesses. Polar-axis (00l)-oriented epitaxial (Bi,K)TiO₃ films were obtained without a secondary phase and/or other orientation for all thickness ranges. Large ferroelectricity with the remanent polarization ( P_r) of about 84 µC/cm², comparable to previously reported lead-based ferroelectric films, was observed for (Bi,K)TiO₃ films down to 33 nm in thickness. On the other hand, E_c increased with decreasing film thickness, but did not show strong film thickness dependence like other perovskite ferroelectric films. These data are very useful for understanding the degradation mechanism of ferroelectric thin films.

DOI： 10.1063/5.0084170

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0074884

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1002/pssr.202100574

researchmap

その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/pssr.202100574

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

DOI： 10.1063/5.0075014

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Ceramic Society of Japan  

DOI： 10.2109/jcersj2.21115

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Objective The relationship between cardiovascular disease and the serum polyunsaturated fatty acid parameters has been reported. The aim of the present study was to investigate the association between the eicosapentaenoic acid and arachidonic acid (EPA/AA) ratio and long-term cardiovascular events in patients with coronary artery disease. Methods We identified a total of 831 patients who underwent percutaneous coronary intervention and whose EPA/AA ratio was available. The patients were divided into two groups according to their serum EPA/AA ratio (median, 0.29; interquartile range 0.19-0.47): those in the lower quartile of EPA/AA ratios (Low EPA/AA group; n=231) and all other subjects (High EPA/AA group; n=600). The primary endpoints included a composite of cardiovascular death, myocardial infarction, and ischemic stroke. Results Patients in the Low EPA/AA group were significantly younger (66.0±12.6 years vs. 69.9±9.3 years, p<0.001), current smokers (33.3% vs. 22.7%, p=0.002), and had a history of myocardial infarction (20.3% vs. 12.3%, p=0.003). During the follow-up (median, 1,206 days; interquartile range, 654-1,910 days), the occurrence of the primary endpoint was significantly higher in the Low EPA/AA group than in the High EPA/AA group. Of note, the rate of cardiovascular death was significantly higher in the Low EPA/AA group, and the rates of myocardial infarction and stroke tended to be higher. Conclusion A low EPA/AA ratio was associated with long-term adverse cardiovascular events in Japanese patients with coronary artery disease.

DOI： 10.2169/internalmedicine.7336-21

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevMaterials.5.114407

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：{IOP} Publishing  

DOI： 10.35848/1347-4065/ac10f8

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac10f8/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/adfm.202108876

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society ({ACS})  

Strong electromechanical coupling is observed in tetragonal Pb-free 0.7(Bi0.5Na0.5)TiO3-0.3BaTiO3 films, which is far from the morphotropic phase boundary, prepared by pulsed laser deposition on a Si substrate. The tensile strain induced during cooling causes in-plane polarization in an oriented film on a Si substrate, while an epitaxial film grown on a SrTiO3 substrate exhibits out-of-plane polarization. S-E curve analysis reveals that the obtained piezoelectric coefficient for the film on the Si substrate (d33,f ≈ 275 pm/V) is approximately eight times higher than that for the epitaxial film on the SrTiO3 substrate (d33,f ≈ 34 pm/V). In situ X-ray diffraction analysis confirms the occurrence of domain switching under an electric field from in-plane to out-of-plane polarization. An effective piezoelectric stress coefficient, e31,eff, of ∼19 C/m2 is obtained from a Si cantilever sample, which is the highest among the reported values for Pb-free piezoelectric films and is comparable to those for Pb-based films. The significant piezoelectric response produced by domain switching in the Pb-free materials with the composition far from the morphotropic phase boundary will expand future applications due to their both outstanding properties and environmental sustainability.

DOI： 10.1021/acsami.1c15713

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

DOI： 10.1063/5.0068059

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0063385

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1002/pssa.202170049

researchmap

その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/pssa.202100302

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/ius52206.2021.9593374

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：{IOP} Publishing  

DOI： 10.35848/1882-0786/ac2261

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1882-0786/ac2261/pdf

Emergent functionalities of structural and topological defects in
ferroelectric materials underpin an extremely broad spectrum of applications
ranging from domain wall electronics to high dielectric and electromechanical
responses. Many of these have been discovered and quantified via local scanning
probe microscopy methods. However, the search for these functionalities has
until now been based by either trial and error or using auxiliary information
such as topography or domain wall structure to identify potential objects of
interest based on the intuition of operator or preexisting hypotheses, with
subsequent manual exploration. Here, we report the development and
implementation of a machine learning framework that actively discovers
relationships between local domain structure and polarization switching
characteristics in ferroelectric materials encoded in the hysteresis loop. The
latter and descriptors such as nucleation bias, coercive bias, hysteresis loop
area, or more complex functionals of hysteresis loop shape and corresponding
uncertainties are used to guide the discovery via automated piezoresponse force
microscopy (PFM) and spectroscopy experiments. As such, this approach combines
the power of machine learning methods to learn the correlative relationships
between high dimensional data, and human-based physics insights encoded in the
acquisition function. For ferroelectric, this automated workflow demonstrates
that the discovery path and sampling points of on-field and off-field
hysteresis loops are largely different, indicating the on-field and off-field
hysteresis loops are dominated by different mechanisms. The proposed approach
is universal and can be applied to a broad range of modern imaging and
spectroscopy methods ranging from other scanning probe microscopy modalities to
electron microscopy and chemical imaging.

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2108.06037v2

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

DOI： 10.35848/1347-4065/ac13d9

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac13d9/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

DOI： 10.35848/1347-4065/ac17e0

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac17e0/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

DOI： 10.35848/1347-4065/ac10f7

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac10f7/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.21002

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Polarization dynamics in ferroelectric materials are explored via the
automated experiment in Piezoresponse Force Spectroscopy. A Bayesian
Optimization framework for imaging is developed and its performance for a
variety of acquisition and pathfinding functions is explored using previously
acquired data. The optimized algorithm is then deployed on an operational
scanning probe microscope (SPM) for finding areas of large electromechanical
response in a thin film of PbTiO3, with metrics showing gains of ~3x in the
sampling efficiency. This approach opens the pathway to perform more complex
spectroscopies in SPM that were previously not possible due to time constraints
and sample stability, tip wear, and/or stochastic sample damage that occurs at
specific, a priori unknown spatial positions. Potential improvements to the
framework to enable the incorporation of more prior information and improve
efficiency further are discussed.

DOI： 10.1021/acsnano.0c10239

PubMed

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2011.13050v2

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

<title>Abstract</title>
Electro-optic (EO) modulators for silicon photonics using CMOS-compatible materials and processes are in great demand. In this study, epitaxial (100)-undoped HfO₂ and Y-doped HfO₂ thin films were fabricated on Sn-doped In₂O₃/yttria-stabilized zirconia(100) substrates at room temperature via magnetron sputtering. EO measurement of the Y-HfO₂ film using modulation ellipsometry showed that the phase was changed by 180° after application of positive and negative poling biases, and the modulation amplitude increased linearly with increasing AC electric field, indicating a linear EO effect based on ferroelectricity. The observed results indicate that ferroelectric HfO₂-based films are viable candidates for CMOS-compatible EO devices.

DOI： 10.35848/1347-4065/ac087d

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ac087d/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsaelm.1c00342

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Electrical and Electronics Engineers Inc.  

DOI： 10.1109/ISAF51943.2021.9477316

Scopus

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1002/pssr.202170023

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/pssr.202000589

Web of Science

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0040934

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/abe72e

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Epicardial adipose tissue (EAT) is considered to play a critical role in vascular endothelial function. Coronary artery spasm has been postulated to be a causal factor in vascular endothelial abnormalities and atherosclerosis. This study aimed to investigate the relationship between coronary artery spasm and EAT volume, total abdominal adipose tissue (AAT) area, and abdominal visceral adipose tissue (AVAT) area. METHOD: Among patients undergoing coronary computed tomography (CT) to evaluate coronary artery disease, we identified 110 patients who did not have significant coronary artery stenosis and underwent a coronary spasm provocation test with cardiac catheterization. They were divided into two groups according to the results of the spasm provocation test: spasm-positive and spasm-negative. EAT volume, total AAT area, and AVAT area were evaluated using CT images. RESULTS: Seventy-seven patients were included in the spasm-positive group and 33 patients in the spasm-negative group. There were no significant differences in baseline clinical characteristics between the two groups, except for the prevalence of current smoking (48% vs. 27%, p = 0.04). EAT volume was significantly higher in the spasm-positive group (108 ± 38 mL vs. 87 ± 34 mL, p = 0.007), while no significant difference was seen in total AAT area (280 ± 113 cm2 vs. 254 ± 128 cm2, p = 0.32) or AVAT area (112 ± 54 cm2 vs. 98 ± 55 cm2, p = 0.27). Multivariate logistic analysis indicated that EAT volume (per 10 cm3) (odds ratio, 1.198; 95% confidence interval, 1.035-1.388; p = 0.016) was a significant predictor of coronary artery spasm. CONCLUSION: Our results suggest that EAT has a strong association with coronary artery spasm, while AAT may not.

DOI： 10.1016/j.ijcard.2020.09.074

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0031803

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

DOI： 10.1063/5.0029630

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nature Research  

DOI： 10.1038/s41524-020-00405-4

Scopus

researchmap

記述言語：英語   出版者・発行元：特定非営利活動法人 超音波エレクトロニクス協会  

DOI： 10.24492/use.41.0_2pb4-4

CiNii Research

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/abad45

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/aba9b3

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s11664-020-08510-2

researchmap

その他リンク： https://link.springer.com/article/10.1007/s11664-020-08510-2/fulltext.html

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

DOI： 10.1063/5.0015281

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electrical and Electronics Engineers Inc.  

DOI： 10.1109/TED.2020.3008891

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society ({ACS})  

DOI： 10.1021/acs.cgd.0c00754

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AIP Publishing  

DOI： 10.1063/5.0017990

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1038/s41524-020-00384-6

researchmap

その他リンク： http://www.nature.com/articles/s41524-020-00384-6

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The universal tendency in scanning probe microscopy (SPM) over the last two
decades is to transition from simple 2D imaging to complex detection and
spectroscopic imaging modes. The emergence of complex SPM engines brings forth
the challenge of reliable data interpretation, i.e. conversion from detected
signal to descriptors specific to tip-surface interactions and subsequently to
materials properties. Here, we implemented a Bayesian inference approach for
the analysis of the image formation mechanisms in band excitation (BE) SPM.
Compared to the point estimates in classical functional fit approaches,
Bayesian inference allows for the incorporation of extant knowledge of
materials and probe behavior in the form of corresponding prior distribution
and return the information on the material functionality in the form of readily
interpretable posterior distributions. We note that in application of Bayesian
methods, special care should be made for proper setting on the problem as model
selection vs. establishing practical parameter equivalence. We further explore
the non-linear mechanical behaviors at topological defects in a classical
ferroelectric material, PbTiO3. We observe the non-trivial evolution of Duffing
resonance frequency and the nonlinearity of the sample surface, suggesting the
presence of the hidden elements of domain structure. These observations suggest
that the spectrum of anomalous behaviors at the ferroelectric domain walls can
be significantly broader than previously believed and can extend to
non-conventional mechanical properties in addition to static and microwave
conductance.

DOI： 10.1063/5.0005323

arXiv

researchmap

その他リンク： http://arxiv.org/pdf/2002.08391v1

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society (ACS)  

Domains walls and topological defects in ferroelectric materials have emerged
as a powerful new paradigm for functional electronic devices including memory
and logic. Similarly, wall interactions and dynamics underpin a broad range of
mesoscale phenomena ranging from giant electromechanical responses to memory
effects. Exploring the functionalities of individual domain walls, their
interactions, and controlled modifications of the domain structures is crucial
for applications and fundamental physical studies. However, the dynamic nature
of these features severely limits studies of their local physics since
application of local biases or pressures in piezoresponse force microscopy
induce wall displacement as a primary response. Here, we introduce a
fundamentally new approach for the control and modification of domain
structures based on automated experimentation whereby real space image-based
feedback is used to control the tip bias during ferroelectric switching,
allowing for modification routes conditioned on domain states under the tip.
This automated experiment approach is demonstrated for the exploration of
domain wall dynamics and creation of metastable phases with large
electromechanical response.

DOI： 10.1021/acsnano.0c04601

PubMed

arXiv

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Ceramic Society of Japan  

DOI： 10.2109/jcersj2.20023

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Ceramic Society of Japan  

DOI： 10.2109/jcersj2.19234

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.20019

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0012998

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media {LLC}  

DOI： 10.1007/s10853-020-04663-x

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/5.0012635

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：{IOP} Publishing  

DOI： 10.35848/1347-4065/aba2bf

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：{IOP} Publishing  

DOI： 10.35848/1347-4065/aba50e

researchmap

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/aba50e/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society (ACS)  

DOI： 10.1021/acsaelm.0c00220

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/ab6b7c

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.35848/1347-4065/ab6d84

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5140612

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1557/adv.2020.99

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/1347-4065/ab65b0

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/1347-4065/ab645b

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1557/adv.2020.67

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/D0TC00821D

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Cambridge University Press  

DOI： 10.1017/S1431927620020528

Scopus

researchmap

記述言語：英語   出版者・発行元：特定非営利活動法人 超音波エレクトロニクス協会  

DOI： 10.24492/use.40.0_3j1-1

CiNii Research

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevLett.123.217601

Web of Science

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/1347-4065/ab3a18

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japan Society of Applied Physics  

DOI： 10.7567/1347-4065/ab36cf

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japan Society of Applied Physics  

DOI： 10.7567/1347-4065/ab37ef

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/1347-4065/ab3a11

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/1347-4065/ab3958

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevB.100.104116

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.mtla.2019.100375

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

Thin films of BaCe0.8Y0.2O3−δ (BCYO) and SrZr0.8Y0.2O3-δ (SZYO) with a perovskite structure were deposited on (111)Pt//(111)SrTiO3 (STO) single crystal substrates by an RF-magnetron sputtering method. X-ray diffraction revealed that the BCYO and SZYO thin films were polycrystalline but highly (110)-one-axis oriented with local epitaxy on (111)Pt//(111)STO in the 〈110〉-direction. However, these films have six-fold symmetric domains and each domain showed in-plane rotations because of the lattice mismatches between (110)BCYO or (110)SZYO and (111)Pt. Especially, the BCYO film showed larger in-plane rotation than that of SZYO because of its larger lattice mismatch.

DOI： 10.7567/1347-4065/ab361f

researchmap

その他リンク： http://iopscience.iop.org/article/10.7567/1347-4065/ab361f/pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5097880

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.19008

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5097980

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.19041

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.19016

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Recent research on piezoelectric materials is predominantly devoted to enhancing the piezoelectric coefficient, but overlooks its sign, largely because almost all of them exhibit positive longitudinal piezoelectricity. The only experimentally known exception is ferroelectric polymer poly(vinylidene fluoride) and its copolymers, which condense via weak van der Waals (vdW) interaction and show negative piezoelectricity. Here we report quantitative determination of giant intrinsic negative longitudinal piezoelectricity and electrostriction in another class of vdW solids-two-dimensional (2D) layered ferroelectric CuInP2S6. With the help of single crystal x-ray crystallography and density-functional theory calculations, we unravel the atomistic origin of negative piezoelectricity in this system, which arises from the large displacive instability of Cu ions coupled with its reduced lattice dimensionality. Furthermore, the sizable piezoelectric response and negligible substrate clamping effect of the 2D vdW piezoelectric materials warrant their great potential in nanoscale, flexible electromechanical devices.

DOI： 10.1126/sciadv.aav3780

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jcrysgro.2019.01.019

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5083941

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1557/adv.2019.129

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.18178

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/1347-4065/aafed1

Web of Science

researchmap

記述言語：英語   掲載種別：論文集(書籍)内論文   出版者・発行元：Elsevier  

DOI： 10.1016/B978-0-08-102430-0.00012-7

Scopus

researchmap

記述言語：英語   掲載種別：論文集(書籍)内論文   出版者・発行元：Elsevier  

DOI： 10.1016/B978-0-08-102430-0.00004-8

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.cap.2019.01.010

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jcrysgro.2018.10.022

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5063712

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5063757

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5055258

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.18149

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.tsf.2018.10.052

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

AIM: Increased epicardial fat volume (EFV) is an independent risk factor for acute coronary syndrome (ACS). Although EFV increases with body mass index (BMI), some ACS patients have an increased EFV but normal BMI. We here investigated the clinical characteristics of nonobese ACS patients with an increased EFV. METHODS: A total of 197 Japanese patients hospitalized for ACS was evaluated for EFV, abdominal visceral fat area (VFA), and lipid and glucose profiles. Control subjects comprised 141 individuals who were suspected of having ACS but whose coronary computed tomography findings were normal. RESULTS: EFV was increased in ACS patients compared with control subjects (120±47 versus 95±45 mL, P＜0.01). ACS patients were divided into four groups based on average EFV (120 mL) and a BMI obesity cutoff of 25 kg/m2. For the 30 nonobese ACS patients with an above-average EFV, EFV was positively correlated with VFA (r=0.23, P=0.031). These individuals were significantly older (74±10 years) and tended to have a higher homeostasis model assessment-insulin resistance value (5.5±3.8) compared with other ACS patients. Among nonobese study subjects, EFV was independently associated with ACS (odds ratio=2.01, P=0.021) and correlated with abdominal circumference (r=0.26, P=0.017). CONCLUSION: Nonobese ACS patients with an increased EFV were elderly and tended to manifest insulin resistance. Measurement of EFV may prove informative for evaluation of ACS risk among elderly nonobese individuals with an increased abdominal girth.

DOI： 10.5551/jat.42663

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2497/jjspm.65.673

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.57.11UF15

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.57.11UF16

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.57.11UF06

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5040018

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5042470

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japan Society of Applied Physics  

DOI： 10.7567/JJAP.57.11UF04

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.57.11UF02

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.57.0902B8

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.57.0902B5

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.57.0902BA

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.17247

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.17251

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10853-017-1902-z

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1557/adv.2018.150

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Scientific Publishers  

DOI： 10.1166/sam.2018.2852

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：SPIE  

DOI： 10.1117/12.2289984

Scopus

researchmap

DOI： 10.7566/JPSCP.21.011047

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.mssp.2016.11.032

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.mssp.2016.12.008

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Scientific Publishers  

DOI： 10.1166/sam.2017.2805

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1166/sam.2017.2808

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.56.10PF09

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.56.10PF12

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.56.10PF16

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Physics  

The effect of strain on the electrocaloric effect in (001)-epitaxial (Ba,Sr)TiO<inf>3</inf>(BST) thin films was experimentally investigated via indirect estimation by measuring the electric field dependence of polarization at various temperatures. Compressively strained (Ba<inf>0.3</inf>Sr<inf>0.7</inf>)TiO<inf>3</inf>films were deposited on (001)cSrRuO<inf>3</inf>/(001)SrTiO<inf>3</inf>and (001)cSrRuO<inf>3</inf>/(001)(La<inf>0.3</inf>Sr<inf>0.7</inf>)(Al<inf>0.65</inf>Ta<inf>0.35</inf>)O<inf>3</inf>(LSAT) by RF magnetron sputtering. The BST film on (001)cSrRuO<inf>3</inf>/(001)SrTiO<inf>3</inf>showed a higher ferroelectric-to-paraelectric phase transition temperature than that on (001)cSrRuO<inf>3</inf>/(001)LSAT owing to the larger compressive strain. It was revealed that the electrocaloric effect is maximized at around the ferroelectric-to-paraelectric phase transition temperature modified by the compressive strain in the films.

DOI： 10.7567/JJAP.56.10PF15

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Physics  

For the application of electronic devices using ferroelectric/piezoelectric components, one-axis-oriented tetragonal Pb(Zr<inf>0.40</inf>Ti<inf>0.60</inf>)O<inf>3</inf>(PZT) films with thicknesses of up to 1 µm were fabricated with the aid of a Ca<inf>2</inf>Nb<inf>3</inf>O<inf>10</inf>nanosheet (ns-CN) template for preferential crystal growth for evaluating their polarization switching behavior. The ns-CN template was supported on ubiquitous silicon (Si) wafer by a simple dip coating technique, followed by the repetitive chemical solution deposition (CSD) of PZT films. The PZT films were grown successfully with preferential crystal orientation of PZT(100) up to the thickness of 1020 nm. The (100)-oriented PZT film with ∼1 µm thickness exhibited unique polarization behavior of ferroelectric polarization, i.e., a marked increase in remanent polarization (P<inf>r</inf>) up to approximately 40 µC/cm²induced by domain switching under high electric field, whereas the film with a lower thickness showed only a lower P<inf>r</inf>of approximately 11 µC/cm²even under a high electric field. The ferroelectric property of the (100)-oriented PZT film after domain switching on ns-CN/Pt/Si can be comparable to those of (001)/(100)-oriented epitaxial PZT films.

DOI： 10.7567/JJAP.56.10PF10

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Physics  

(111)-oriented epitaxial (K<inf>0.5</inf>Na<inf>0.5</inf>)NbO<inf>3</inf>films of 2 µm thickness were deposited at 240 °C on (111)<inf>c</inf>SrRuO<inf>3</inf>//(111)SrTiO<inf>3</inf>substrates by a hydrothermal method. Scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy (STEM-EDS) mapping revealed that a K-rich interfacial region existed in the obtained films. Although the as-deposited films were annealed between 240 and 600 °C in O<inf>2</inf>atmosphere, the crystal structure did not markedly change. On the other hand, the leakage current density drastically decreased from 10⁻²–10⁰to 10⁻⁶A/cm²at ±80 kV/cm after annealing above 240 °C. In addition, the relative dielectric constant (ε<inf>r</inf>), remanent polarization (P<inf>r</inf>), and piezoelectric constant (d<inf>33,PFM</inf>) increased with increasing annealing temperature from 300 to 600 °C, and their values were respectively 840, 5.7 µC/cm², and 64 pm/V for the films annealed at 600 °C.

DOI： 10.7567/JJAP.56.10PF04

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41598-017-09389-6

Web of Science

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.5000495

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ceramint.2017.05.253

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41598-017-05475-x

Web of Science

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Japan Society of Applied Physics  

DOI： 10.7567/JJAP.56.06HE03

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10853-017-0927-7

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jcrysgro.2016.12.032

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.56.05DC02

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4983381

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/aelm.201600508

Web of Science

CiNii Research

researchmap

記述言語：英語   出版者・発行元：Institute of Physics  

Mg<inf>2</inf>Si thin films were deposited at 320 °C on (001)Al<inf>2</inf>O<inf>3</inf>and (100)CaF<inf>2</inf>substrates by radio-frequency magnetron sputtering. Both films showed a preferential (111) out-of-plane orientation with an in-plane random orientation irrespective of post-heat treatment. Mg<inf>2</inf>Si films on (001)Al<inf>2</inf>O<inf>3</inf>substrates were under in-plane tensile strain, while those on (100)CaF<inf>2</inf>substrates were under in-plane compressive strain both before and after heat treatment. Heat-treated films showed p-type conduction up to 500 °C. Their electrical conductivity and Seebeck coefficient were almost independent of the kind of substrate within the limit of the present study, from 0.22% compressive strain to 0.34% tensile strain at room temperature.

DOI： 10.7567/JJAP.56.05DC02

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4978649

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.sse.2016.10.007

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.16326

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.16283

Web of Science

researchmap

記述言語：日本語   出版者・発行元：一般社団法人 日本物理学会  

DOI： 10.11316/jpsgaiyo.72.2.0_2282

CiNii Research

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/00150193.2017.1349994

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.16262

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1557/adv.2017.221

Web of Science

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1109/TUFFC.2016.2569625

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.55.10TC07

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.55.10TA08

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.55.10TA19

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Physics  

Artificial superlattice thin films consisting of two different compositions of Pb(Zr,Ti)O<inf>3</inf>(PZT), which are in tetragonal and rhombohedral phases at room temperature in the bulk state, were grown on (111)<inf>c</inf>SrRuO<inf>3</inf>/(111)SrTiO<inf>3</inf>by pulsed laser deposition. Fairly perfect periodicity with sharp interfaces was observed by X-ray diffraction and scanning transmission electron microscopy. It was found that the film with each layer of 5 nm thickness had a single-domain structure for both PZT layers, which would arise from the strong mechanical and electrical coupling between PZT layers. The fabricated superlattice thin films showed saturated P–E hysteresis curves. Larger electromechanical response was observed in the films with smaller layer thickness.

DOI： 10.7567/JJAP.55.10TA20

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Physics  

In the present work, we aim to achieve the preferred crystal orientation of chemical solution deposition (CSD)-derived BaTiO<inf>3</inf>films on ubiquitous Si wafers with the assistance of Ca<inf>2</inf>Nb<inf>3</inf>O<inf>10</inf>nanosheet (ns-CN) template layers. The ns-CN on platinized Si (Pt/Si) substrates aligned the BaTiO<inf>3</inf>(100) plane to the substrate surface, because of the favorable lattice matching of the ns-CN (001) plane. The CSD process in air required a high crystallization temperature of 900 °C for the preferred crystal orientation of BaTiO<inf>3</inf>(100) because of the BaCO<inf>3</inf>byproduct generated during the combustion reaction of the precursor gel. The processing in vacuum to remove CO<inf>2</inf>species enhanced the crystal orientation even at the crystallization temperature of 800 °C, although it can generate oxygen vacancies ([Formula: see text]) that cause distorted polarization behavior under an applied field higher than approximately 150 kV/cm. The relative dielectric constant (ε<inf>r</inf>) of the (100)-oriented BaTiO<inf>3</inf>film on the ns-CN-supported Pt/Si substrate (ns-CN/Pt/Si) was generally larger than that of the randomly oriented film on Pt/Si, depending on the degree of crystal orientation.

DOI： 10.7567/JJAP.55.10TA15

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4962431

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/srep32931

Web of Science

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4960461

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/aelm.201600170

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND AND AIMS: Omentin, an adipocytokine secreted by visceral adipose tissue, protects against obesity-linked cardiovascular complications. However, little is known about its role in epicardial adipose tissue (EAT) and coronary artery disease (CAD). We investigated the expression of omentin in EAT from CAD subjects. METHODS: EAT, subcutaneous adipose tissue (SCAT), and plasma samples were collected from CAD (n = 15; 23.3 ± 3.1 kg/m(2)) and non-CAD patients (n = 10; 20.8 ± 3.9 kg/m(2)). Omentin mRNA expression was measured using real-time PCR, while plasma concentrations were measured using an ELISA. EAT volume was determined with 64-slice computed tomography. RESULTS: Omentin expression in EAT and EAT volume were higher in CAD patients compared with controls (2.49 ± 2.6 vs. 0.85 ± 0.3, p = 0.002 and 113 ± 58 ml vs. 92.4 ± 30 ml, p = 0.045, respectively). Omentin expression in SCAT was similar between CAD and control patients (1.37 ± 0.84 vs. 1.07 ± 0.55, p = 0.267). Plasma omentin levels were lower in CAD patients compared with controls (343 ± 158 ng/ml vs. 751 ± 579 ng/ml, p = 0.025), and were negatively associated with the expression of omentin in EAT, in patients with CAD (β = -0.78, p = 0.049). On the other hand, there was no association between omentin in EAT and clinical variables in patients with non-CAD. CONCLUSIONS: Omentin expression increases in the EAT of non-obese CAD patients, despite a decrease in plasma levels, suggesting that omentin may play a role in the pathogenesis of CAD.

DOI： 10.1016/j.atherosclerosis.2016.07.003

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4954942

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.55.06HC02

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.16024

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.15321

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4951672

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.15245

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4945029

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1557/jmr.2016.56

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/srep20713

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.55.02BC19

Web of Science

researchmap

記述言語：英語   出版者・発行元：Institute of Physics  

A proton-conductive BaCe<inf>0.9</inf>Y<inf>0.1</inf>O<inf>3−δ</inf>(BCYO) thin-film, one of the candidates for the electrolyte of intermediate-temperature solid oxide fuel cells (IT-SOFCs), was deposited on (111)Pt/TiO<inf>2</inf>/SiO<inf>2</inf>/(100)Si substrate by the RF magnetron sputtering method. The sputtering conditions, i.e., deposition temperature, pressure, and sputtering gases, were examined to improve the crystallinity of the films. The BCYO films deposited at more than 500 °C were well crystallized and showed only 110 diffraction. The addition of O<inf>2</inf>into the sputtering gas causes adverse results of lower crystallinity and lower deposition rates. A wide-range XRD reciprocal space mapping also revealed that the (110)-oriented BCYO films can be obtained on (111)Pt/TiO<inf>2</inf>/SiO<inf>2</inf>/(100)Si substrates without the need to use any buffer layers. We consider that this BCYO film possibly shows high proton conductivity and may be a suitable material for the SOFC electrolyte because of its high crystallinity.

DOI： 10.7567/JJAP.55.02BC19

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4939818

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jallcom.2015.09.109

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1117/12.2212057

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4941803

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11664-016-4404-x

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.55.10TA13

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.tsf.2015.12.067

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4937456

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ceramint.2015.03.184

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.54.10NA15

Web of Science

researchmap

その他リンク： http://stacks.iop.org/1347-4065/54/i=10S/a=10NA15?key=crossref.6af14dd16c2b05830cc0242152b24d2e

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.54.10NA07

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chinese Ceramic Society  

DOI： 10.1016/j.jmat.2015.07.004

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The ferroelectric properties and crystal structure of doped HfO2 thin films were investigated for different thicknesses, electrode materials and annealing conditions. Metal-ferroelectric-metal capacitors containing Gd:HfO2 showed no reduction of the polarization within the studied thickness range, in contrast to hafnia films with other dopants. A qualitative model describing the influence of basic process parameters on the crystal structure of HfO2 was proposed. The influence of different structural parameters on the field cycling behavior was examined. This revealed the wake-up effect in doped HfO2 to be dominated by interface induced effects, rather than a field induced phase transition.

DOI： 10.1063/1.4927805

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4927810

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.54.10ND06

Web of Science

CiNii Research

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4927450

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4927208

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4926963

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.54.07JC01

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/physrevb.91.214101

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/ISAF.2015.7172698

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.energy.2015.04.060

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2109/jcersj2.123.322

researchmap

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/admi.201500075

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1063/1.4915336

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.54.035501

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Electrical and Electronics Engineers Inc.  

DOI： 10.1109/MEMSYS.2015.7051155

Scopus

researchmap

記述言語：英語   出版者・発行元：Institute of Physics  

Epitaxial BaTiO<inf>3</inf>(BTO) thin films of less than 100 nm thickness were grown on Pt(001)/MgO(001) substrates at growth temperatures of 500–700 °C with a low deposition rate of about 25 nm/h by metal–organic chemical vapor deposition (MOCVD). The BaTiO<inf>3</inf>thin films were epitaxialy grown with (001) orientation. These films show quadrangular grains and a dense cross-sectional structure. The relative permittivities of these films grown at 500, 600, and 700 °C with thicknesses of 62, 65, and 82 nm were 338, 455, and 566 at 1 kHz, respectively. These relative permittivities were higher than those of BTO films prepared by other methods and BTO ceramics with thicknesses less than 100 nm.

DOI： 10.7567/JJAP.54.035501

researchmap

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1557/opl.2015.95

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Materials Research Society  

DOI： 10.1557/opl.2015.54

Scopus

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1117/12.2079405

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1088/1742-6596/660/1/012057