Article
Physics, Applied
Michael R. Walden, Cristian V. Ciobanu, Geoff L. Brennecka
Summary: This study validates the use of metrics of localized electronic states in predicting the trends in ferroic and dielectric properties of BiFeO3 and BiCrO3 under epitaxial strain using density-functional theory. The results suggest that localized electronic metrics can accurately predict the multiferroic characteristics of these systems, providing specific strain ranges.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Cameliu Himcinschi, Felix Drechsler, David Sebastian Walch, Akash Bhatnagar, Alexei A. Belik, Jens Kortus
Summary: The dielectric function and bandgap of BiFe0.5Cr0.5O3 thin films were measured using spectroscopic ellipsometry and compared with BiFeO3 and BiCrO3. A lower bandgap was observed in BiFe0.5Cr0.5O3 due to an optical transition between Cr and Fe ions. Raman spectroscopy revealed the presence of new phonon modes in the thin films and bulk samples, and temperature-induced structural phase transitions were studied in BiFe0.3Cr0.7O3.
Article
Chemistry, Physical
Yaoxiang Jiang, Xin Wu, Jianguo Niu, Yunpeng Zhou, Ning Jiang, Fei Guo, Bo Yang, Shifeng Zhao
Summary: Switchable polarization behavior at room temperature is achieved in [(La2NiMnO6)/(La2CoMnO6)](n) double-perovskite magnetic superlattice films by engineering a microstructure with gradient strains, while the ferromagnetic Curie temperature does not show rapid decrease.
Article
Chemistry, Physical
August E. G. Mikkelsen, Jakob Schiotz, Tejs Vegge, Karsten W. Jacobsen
Summary: The study reveals that the water/Pt(111) interface is characterized by a double layer structure involving a primary strongly bound adsorption layer and a secondary weakly bound adsorption layer. There is effective repulsion between the adsorbed water molecules, resulting in a dynamically changing, semi-ordered interfacial structure.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Engineering, Environmental
Yuanyuan Wu, Ji Li, Mingsong Lv, Xianfa Zhang, Rui Gao, Chuanyu Guo, Xiaoli Cheng, Xin Zhou, Yingming Xu, Shan Gao, Zoltan Major, Lihua Huo
Summary: Carbon monoxide (CO) intoxication incidents have been occurring frequently in recent years, highlighting the importance of sensitive CO detection. Most currently reported CO sensors have the disadvantage of requiring high working temperatures, making it a challenge to achieve sensitive detection at room temperature. In this study, CuO nanosheets with exposed active crystal facets and oxygen vacancy defects were successfully synthesized using a simple and environmentally friendly hydrothermal method. The sensor exhibited excellent comprehensive gas sensing performance, surpassing other sensors in detecting CO at room temperature. The response value to 100 ppm CO at room temperature reached as high as 39.6. Additionally, the sensor demonstrated excellent selectivity, low detection limit (100 ppb), good reproducibility, moisture resistance, and long-term stability (60 days). These outstanding gas sensing capabilities can be attributed to the unique structural characteristics of the 2D materials and the synergistic effect of the exposed active crystal facets and oxygen vacancy defects. Therefore, this sensor is expected to become a promising sensitive material for rapid and accurate detection of trace CO gas with low energy consumption, reducing the risk of poisoning and effectively protecting human life safety.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Article
Multidisciplinary Sciences
Hariom Jani, Jheng-Cyuan Lin, Jiahao Chen, Jack Harrison, Francesco Maccherozzi, Jonathon Schad, Saurav Prakash, Chang-Beom Eom, A. Ariando, T. Venkatesan, Paolo G. Radaelli
Summary: In the quest for post-CMOS technologies, researchers have shown promising results in experimenting with topologically protected ferromagnetic whirls such as skyrmions and their anti-particles, which can serve as solitonic information carriers. Antiferromagnetic analogues have become the subject of intense focus due to their predicted relativistic dynamics and potential for fast deflection-free motion and size scaling, although experimental demonstration in natural antiferromagnetic systems has yet to be achieved. By utilizing a first-order analogue of the Kibble-Zurek mechanism, a family of topological antiferromagnetic spin textures has been stabilized on an Earth-abundant oxide insulator, showing potential for low-energy antiferromagnetic spintronics at room temperature.
Article
Physics, Multidisciplinary
Zishen Tian, Michael Xu, Jieun Kim, Hao Pan, Djamila Lou, Xiaoxi Huang, James M. Lebeau, Lane W. Martin
Summary: Superlattices of [BaTiO3]m/[BaZrO3]n (m, n = 4-12) are used to demonstrate the fabrication and control of an artificial relaxor. Experimental results show the successful production of high-quality heterostructures. The study reveals a transition in the dielectric properties of the materials as the BaTiO3 layer thickness decreases.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Geoffroy Kremer, Julian Maklar, Laurent Nicolai, Christopher W. Nicholson, Changming Yue, Caio Silva, Philipp Werner, J. Hugo Dil, Juraj Krempasky, Gunther Springholz, Ralph Ernstorfer, Jan Minar, Laurenz Rettig, Claude Monney
Summary: α-GeTe(111) is a non-centrosymmetric ferroelectric semiconductor material with a strong spin-orbit interaction and giant Rashba coupling. Its ferroelectric polarization can be controlled by an electric field at room temperature, and research shows that femtosecond light pulses can modulate the Rashba coupling and enhance the lattice distortion on a femtosecond timescale.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Sebastian Schneider, Kushtrim Bytyqi, Stephan Kohaut, Patrick Buegel, Benjamin Weinschenk, Michael Marz, Amina Kimouche, Karin Fink, Regina Hoffmann-Vogel
Summary: The self-assembly behavior of DBBA molecules on Au(111) was investigated using FM-SFM and ab initio calculations. It was found that the assembly morphology of the molecules changes with increasing coverage, and different phases coexist at intermediate coverage. Additionally, the adsorption behavior and interactions of the molecules were discussed and compared with the results from ab initio calculations.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
Changjiang Liu, Xi Yan, Dafei Jin, Yang Ma, Haw-Wen Hsiao, Yulin Lin, Terence M. Bretz-Sullivan, Xianjing Zhou, John Pearson, Brandon Fisher, J. Samuel Jiang, Wei Han, Jian-Min Zuo, Jianguo Wen, Dillon D. Fong, Jirong Sun, Hua Zhou, Anand Bhattacharya
Summary: The study discovers superconductivity in electron gases formed at interfaces between certain materials, with a relatively high superconducting transition temperature and clear two-dimensional superconductivity. In some samples, a spontaneous in-plane transport anisotropy is observed before the onset of superconductivity, indicating the emergence of a distinct stripe-like phase.
Article
Nanoscience & Nanotechnology
O. J. Amin, S. F. Poole, S. Reimers, L. X. Barton, A. Dal Din, F. Maccherozzi, S. S. Dhesi, V. Novak, F. Krizek, J. S. Chauhan, R. P. Campion, A. W. Rushforth, T. Jungwirth, O. A. Tretiakov, K. W. Edmonds, P. Wadley
Summary: Researchers have discovered that topological spin textures can be generated and moved at room temperature using electrical pulses in the semimetallic antiferromagnet CuMnAs, which is a testbed system for spintronic applications. This finding is crucial for realizing the full potential of antiferromagnetic thin films as active components in high-density, high-speed magnetic memory devices.
NATURE NANOTECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
Donghai Li, Chiara Trovatello, Stefano Dal Conte, Matthias Nuss, Giancarlo Soavi, Gang Wang, Andrea C. Ferrari, Giulio Cerullo, Tobias Brixner
Summary: Research on exciton-phonon coupling in single-layer transition metal dichalcogenides has shown stronger coupling compared to most other inorganic semiconductor nanostructures. Utilizing two-dimensional micro-spectroscopy, the study provides a unique tool to measure the characteristics of exciton-phonon coupling and design-relevant parameters for the development of optoelectronic devices.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Salman Ali Khan, Tauseef Ahmed, Muhammad Habib, Fazli Akram, Jihee Bae, Tae Kwon Song, Dong Hwan Lim, Soon-Jong Jeong, Myong-Ho Kim, Soonil Lee
Summary: Introducing BNSTNZ into BF35BT ceramics resulted in a shift from normal-ferroelectric to relaxor-ferroelectric phase, leading to high dynamic piezoelectric coefficient and relatively high static piezoelectric coefficient at the optimum composition. This composition shows great potential for high-temperature piezoelectric applications due to its enhanced field-induced strain response.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2021)
Article
Physics, Applied
Li-Da Chen, Li-Huai Shu, Bi Hui Zhang, Lin Liu, Lin Lei, Ye Shao, Feng-Zhen Huang, Yang-Yang Lv, Zhen-Xiang Cheng, Jian-Li Wang, G. A. Stewart, J. M. Cadogan, W. D. Hutchison, Jian Zhou, Xiao Qiang Liu, Shu-Hua Yao, Y. B. Chen, Yan-Feng Chen
Summary: We grew (Sr, Ca) Nd2Fe2O7 single crystals with the Ruddlesden-Popper structure using an optical floating-zone method. A significantly anisotropic magneto-dielectric effect (MD) was observed in a SrNd2Fe2O7 crystal at room temperature, with ab-plane and c-axial MD coefficients reaching -12.3% and -8.4% in a 1 T magnetic field. The anisotropic MD effect decreased with an increase in Ca concentration and eventually disappeared. The anisotropic MD effect in SrNd2Fe2O7 crystals can be attributed to polaronic hopping between neighboring Fe3+ ions through oxygen vacancies in an anisotropically antiferromagnetic matrix.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Lili Yang, Xinjie Wang, Liang Bai, Lan Xu, Ya Yang
Summary: The research focuses on enhancing the output photocurrent of ferroelectric photovoltaic materials. Considering the effect of increasing temperatures on ferroelectric photovoltaics is crucial due to the operation of solar cells at high temperatures. In this study, an LNO/BFO/ITO device is constructed on a mica substrate, and it achieves output photocurrent enhancement at a wide temperature range. The article investigates the effect of high temperatures on ferroelectric photovoltaics and provides a strategy for enhancing their performance.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Physics, Applied
Yosuke Isoda, Daisuke Kan, Takuya Majima, Yuichi Shimakawa
Summary: We investigated the electrochemical responses of (100), (110), and (111)-oriented oxygen-deficient perovskite SrFeO2.5+y epitaxial films. Only the (100)-oriented films exhibited changes associated with gate-voltage-induced electrochemical reductions. The electrochemically reduced (100) films were found to accommodate protons, forming the proton-containing oxide H0.11SrFeO2.5+y. Our results suggest that oxygen vacancies preferentially form along the {100} axes and ion diffusion in electrochemical reactions predominantly occurs along the {100} directions in SrFeO2.5+y.
APPLIED PHYSICS EXPRESS
(2023)
Article
Chemistry, Physical
Yuki Sakai, Kana Matsuno, Takumi Nishikubo, Masayuki Fukuda, Shogo Wakazaki, Masahito Ikeda, Kazuki Takahashi, Zhao Pan, Lei Hu, Masaki Azuma
Summary: Two different mechanisms of negative thermal expansion (NTE) were observed in the solid solutions of perovskite-type oxides PbCrO3 and PbTiO3. For x <= 0.6, PbCr1-xTixO3 adopted a cubic structure similar to that of PbCrO3, while for x >= 0.7 a PbTiO3-type tetragonal structure was observed. The NTE observed at x <= 0.6 was caused by a cubic-to-cubic phase transition related to the rearrangement of Pb2+/Pb4+ in a charge glass structure. Despite the absence of intermetallic charge transfer, PbCrO3 exhibited a significant volume shrinkage of -2.5%. The NTE in the tetragonal phase was due to a ferroelectric-to-paraelectric phase transition, the same as in PbTiO3. By substituting Cr, the working temperature of PbTiO3 as an NTE material was effectively lowered while maintaining a large volume shrinkage of 0.6%.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Yanjia Zhang, Miho Sawamura, Maho Harada, Yusuke Noda, Masanobu Nakayama, Masato Goto, Daisuke Kan, Yuichi Shimakawa, Benoit Denis Louis Campeon, Daisuke Shibata, Toshiaki Ohta, Naoaki Yabuuchi
Summary: This study investigates the Li3NbO4-CoO binary system and finds that although Li4/3Co2/9Nb4/9O2 exhibits a reversible capacity increase as electrode material, there are irreversible structural changes in its electrochemical cycles, leading to the instability of anionic redox.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Taro Kamada, Taisei Ueda, Shuta Fukuura, Takashi Yumura, Saburo Hosokawa, Tsunehiro Tanaka, Daisuke Kan, Yuichi Shimakawa
Summary: In this study, catalytic model systems based on Pd-loaded SrFeOx films were fabricated to investigate the phenomenon of hydrogen spillover. The results showed that hydrogen spillover on the SrFeOx support can extend over long distances, up to 600 μm. The reduction of Fe4+ on the support surface induced by hydrogen spillover yields large energies, driving the unexpectedly long-distance hydrogen diffusion. These findings provide a deeper understanding of hydrogen spillover and offer insights for designing catalyst systems with enhanced properties.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Ariunzaya Tsogoo, Ninjbadgar Tsedev, Alain Gibaud, Philippe Daniel, Abdelhadi Kassiba, Masayuki Fukuda, Yoshihiro Kusano, Masaki Azuma, Namsrai Tsogbadrakh, Galbadrakh Ragchaa, Rentsenmyadag Dashzeveg, Erdene-Ochir Ganbold
Summary: Copper-doped ZnO nanoparticles were synthesized and their properties were studied. The nanoparticles had a hexagonal wurtzite structure and Cu2+ ions were successfully incorporated in the host ZnO lattice. The photocatalytic activity of the nanoparticles was enhanced, and the presence of unpaired electrons favored a ferromagnetic state.
Article
Chemistry, Physical
Yuichi Shimakawa, Yoshihisa Kosugi
Summary: The caloric effects of solids are important for efficient and environmentally friendly energy systems. Exploring novel caloric materials is challenging but crucial for future technologies. This article highlights two transition-metal oxides that show giant caloric effects: NdCu3Fe4O12 and BiCu3Cr4O12. These compounds exhibit unusual high valence states of transition-metal ions and charge transitions to relieve electronic instabilities, resulting in large caloric responses. The details and mechanism of these giant caloric effects are summarized and discussed.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Chemistry, Inorganic & Nuclear
Masayuki Fukuda, Takumi Nishikubo, Hongwu Yu, Yoichi Okimoto, Shin-ya Koshihara, Kazunari Yamaura, Masaki Azuma
Summary: We have successfully synthesized a new A-site columnar-ordered perovskite compound, CaZnV2O6, and investigated its electronic and magnetic statesexperimentally and computationally. This compound is found to be a Pauli-paramagnetic correlated metal, providing a new playground for electronic and magnetic states of V4+.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Makoto Iihoshi, Masato Goto, Yoshihisa Kosugi, Yuichi Shimakawa
Summary: The A-site layer-ordered double perovskite SmBaFe2O6 is synthesized by oxidizing A-site layer-ordered SmBaFe2O5 in ozone at a low temperature. This compound contains high and mixed valence Fe3.5+ and exhibits cascade charge transitions, represented as SmBa(Fe3+1.5Fe5+0.5)O6, to alleviate its electronic instability. The first Verwey-like charge-order transition occurs at 340 K, accompanied by significant structural changes and a sudden increase in magnetic susceptibility. Subsequently, a charge disproportionation of metastable Fe4+ to Fe3+ and Fe5+ takes place, resulting in an antiferromagnetic ground state. Plausible charge-ordered patterns are proposed based on electrostatic lattice energy calculations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Physics, Applied
Kazuki Arima, Seiji Nakashima, Koji Kimura, Koichi Hayashi, Naohisa Happo, Hironori Fujisawa
Summary: This study investigates the local atomic structure around the Fe site in a V-doped BFO thin film using X-ray fluorescence holography. The results reveal that the atomic structure stability of the V-doped BFO thin film differs from that of previously reported Mn-doped BFO thin films, providing important insights into the mechanism of controlling the conductivity of BFO thin films by dopants.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Takeshi Asuka, Junpei Ouchi, Hironori Fujisawa, Seiji Nakashima
Summary: HZO films prepared via non-heating sputtering are investigated for their application in ferroelectric-gate TFTs. The internal tensile stress induced by ITO top-electrode deposition is found to promote the crystallization of HZO from the amorphous state to the ferroelectric phase. Non-heating process fabricated ITO/HZO/ITO capacitors exhibit ferroelectric hysteresis loops with remanent polarizations of 6-9 μC cm(-2) and coercive fields of 0.6-1.1 MV cm(-1). Non-heating process fabricated ferroelectric-gate TFTs with a 10 nm thick ITO channel show nonvolatile operation with an on/off ratio of ~10.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Masahito Ikeda, Randy Jalem, Gen Hasegawa, Naoaki Kuwata, Qiumin Liu, Takafumi Yamamoto, Kei Shigematsu, Yoshitaka Tateyama, Masaki Azuma
Summary: A new LISICON-type solid-state electrolyte in Li3BO3-Li3PO4-Li2SO4 ternary system was theoretically investigated and predicted to have high Li-ion conductivity. The experimental results, however, showed a lower conductivity, possibly due to structural differences.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Takuya Ohmi, Iain W. H. Oswald, James R. Neilson, Nikolaj Roth, Shunta Nishioka, Kazuhiko Maeda, Kotaro Fujii, Masatomo Yashima, Masaki Azuma, Takafumi Yamamoto
Summary: In this study, a thiocyanate-stabilized pseudo-cubic perovskite FAPbI(3) with ordered columnar defects (alpha'-phase) is reported. The compound is stable at room temperature and the presence of the alpha'-phase reduces the transition temperature of delta-phase to alpha-phase. The defect-ordered pattern in the alpha'-phase forms a coincidence-site lattice at the twinned boundary of the single crystals.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Chen Chen, Yoshihisa Kosugi, Masato Goto, Yuichi Shimakawa
Summary: The thermal properties and phase transition behaviors of Bi(0.95)Ln(0.05)NiO(3) (Ln = La, Nd, Sm, Eu, Gd, Dy) were investigated as potential caloric materials. However, the observed latent heats at the intersite-charge-transfer transition temperatures were not comparable to that of the giant caloric effect compound NdCu3Fe4O12. Contrary to expectations, the magnetic transitions of Ni2+ spins in Bi(0.95)Ln(0.05)NiO(3) were not induced by intersite charge transfer, and the magnetic entropy changes did not contribute to the latent heat produced by these transitions. Materials with intrinsic magnetic transition temperatures much higher than the charge-transfer transition temperatures may be needed to achieve giant caloric effects.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Chemistry, Physical
Yanjia Zhang, Miho Sawamura, Maho Harada, Yusuke Noda, Masanobu Nakayama, Masato Goto, Daisuke Kan, Yuichi Shimakawa, Benoit Denis Louis Campeon, Daisuke Shibata, Toshiaki Ohta, Naoaki Yabuuchi
Summary: In this study, Li3NbO4-CoO binary system was investigated as electrode materials for lithium storage applications. It was found that with the increase of Li3NbO4 fraction, cation-disordered rocksalt structure formed in Li-excess phases, leading to the degradation of performance. Factors affecting the reversibility and irreversibility of anionic redox were further discussed through systematic study of the binary system of Li3NbO4-CoO.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Engineering, Electrical & Electronic
Ryunosuke Takahashi, Takuo Ohkochi, Daisuke Kan, Yuichi Shimakawa, Hiroki Wadati
Summary: Using a magneto-optical Kerr effect (MOKE) microscope, we observed laser-induced magnetization switching in ferrimagnetic oxide NiCo2O4 (NCO) epitaxial thin films with perpendicular magnetic anisotropy. Laser pulses at 1030 nm were used to irradiate the NCO thin film at different temperatures (300-400 K) while altering the parameters of pulse interval, fluence, and the number of pulses in the absence of an external magnetic field. We observed accumulative all-optical helicity-dependent switching above 380 K. Our observation of oxide NCO thin films facilitates magnetization switching using ultrafast lasers without the need for a magnetic field.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
