Article
Chemistry, Multidisciplinary
Yalin Zhang, Wei-Min Zhao, Chunchen Zhang, Peng Wang, Tong Wang, Shao-Chun Li, Zhongwen Xing, Dingyu Xing
Summary: The abnormal superconducting proximity effect (SPE) in a topological insulator/superconductor heterostructure is revealed, occurring in momentum space regardless of the thickness of the topological insulator film. The unique properties of topologically protected surface states of Bi2Se3 induce the SPE-induced superconductivity even in thick films. This research deepens the understanding of the important role of topologically protected surface states in the SPE.
ADVANCED MATERIALS
(2022)
Article
Physics, Applied
Yalin Zhang, Tong Wang, Zhihe Wang, Zhongwen Xing
Summary: The study demonstrates that a stronger matching between the film and substrate is crucial in enhancing the superconducting and magnetic properties of FST films. The FST film on STO substrate exhibits the highest superconducting transition temperature and the largest critical current density.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Physics, Applied
Fan Fan, Xianping Zhang, Chuanbing Cai, Yanwei Ma
Summary: Biaxially textured FeSe0.5Te0.5 (FST) thin films were fabricated with CeO2 buffer layers, showing low misalignment angles, high superconducting transition temperature, and high critical current density. Different J(c) peaks were observed in H//c and H//ab directions at different temperatures, indicating the presence of temperature- and field-dependent pinning mechanisms.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
S. Leith, J. Qiao, M. Vogel, E. Seiler, R. Ries, Y. Li, C. Wiktor, J. Mueller, Y. Sakalli, B. Butz, X. Jiang
Summary: The use of energetic condensation techniques, such as HiPIMS, has the potential to improve the superconducting performance of coated Cu cavities by producing bulk-like Nb thin films. However, a deeper understanding of the effects of deposition parameters, film properties, and superconducting performance is needed. This study explores the effects of different HiPIMS deposition parameters on the morphological, crystallographic, and superconducting properties of Nb thin films deposited onto electropolished Cu substrates. Higher duty cycles, surface smoothness, and transition zones in film growth are observed.
Article
Chemistry, Multidisciplinary
Tao Zhang, Qian Cheng, Yifan Li, Zhiguo Hu, Yuxuan Zhang, Jinbang Ma, Yixin Yao, Yan Zuo, Qian Feng, Yachao Zhang, Hong Zhou, Jing Ning, Chunfu Zhang, Jincheng Zhang, Yue Hao
Summary: In this study, beta-(AlxGa1-x)(2)O-3 films were deposited on c-plane sapphire substrates using metal-organic chemical vapor deposition. It was found that by adjusting the TMAI flow rate or TMAI/(TMAI + TEGa) flow rate ratio, the diffraction peaks and optical band gap of the films could be modified. Furthermore, the deposition temperature also affected the crystal structure and optical properties of the films.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Chemistry, Multidisciplinary
Zainab Fatima, Daichi Oka, Tomoteru Fukumura
Summary: By studying the lattice strain in rutile-type RuO2 epitaxial thin films grown at different temperatures, it was found that the strain is influenced by growth-mode-induced effects and thickness. Within a certain range, the lattice strain had no significant impact on the electrical properties of RuO2, ensuring its reliable applications as catalysts and electrodes.
CRYSTAL GROWTH & DESIGN
(2021)
Article
Physics, Multidisciplinary
Xiang Ding, Shengchun Shen, Huaqian Leng, Minghui Xu, Yan Zhao, Junrui Zhao, Xuelei Sui, Xiaoqiang Wu, Haiyan Xiao, Xiaotao Zu, Bing Huang, Huiqian Luo, Pu Yu, Liang Qiao
Summary: The discovery of superconducting states in the nickelate thin film with infinite-layer structure has provided a new path for studying unconventional superconductivity. The study shows that the superconducting state of Nd0.8Sr0.2NiO2 is remarkably stable in ambient conditions, but disappears when immersed in water.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Physics, Applied
Mengting Si, Chengli Wang, Can Yang, Wei Peng, Lixing You, Zhongxu Li, Hui Zhang, Jia Huang, You Xiao, Jiamin Xiong, Lu Zhang, Yiming Pan, Xin Ou, Zhen Wang
Summary: By depositing NbN superconducting films on different types of LN substrates, it was found that different LN substrates have different thickness dependencies on NbN films' T(c), delta T(c), and residual resistance ratios. By evaluating the cutting selection, it was concluded that X-cut and Y-cut LN are more suitable as a platform for integrated LN photonic chips.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Jia-Ming Zhao, Zhi-He Wang
Summary: In this study, we investigated the anisotropic electrical transport and magnetic properties of FeSe0.5Te0.5 single crystals grown by the self-flux method. The in-plane resistivity exhibited a metallic-like temperature dependence, while the out-of-plane resistivity showed a broad hump at around 64 K. The magnetization loops for H//c-axis and H//ab-plane were also different, with a typical second peak observed for H//c-axis. The in-plane critical current density was higher than the out-of-plane critical current density. The coherence length and penetration depth were estimated using the Ginzburg-Landau theory. The anisotropic parameter gamma depended on the applied magnetic field and temperature. The coupling of superconducting FeSe(Te) layers and the flux pinning mechanism relevant to anisotropy were also discussed.
Article
Chemistry, Physical
Hongyan Zhu, Jishi Cui, Rongrong Chen, Bo Feng, Xinyu Han, Caina Luan, Jin Ma, Hongdi Xiao
Summary: High-quality ZnSnO3 epitaxial films are grown on LiNbO3(0001) substrates by pulsed laser deposition. The properties of the films, such as crystalline quality, composition, surface topography, structure, defect formation energy, and photovoltaic properties, are highly sensitive to changes in the oxygen pressure. The film grown at PO2 = 10 Pa has the highest crystal quality, while the film obtained at PO2 = 0.1 Pa presents the highest responsivity and light/dark current ratio under the 254-nm-light irradiation, indicating its potential for high-performance UV photodetector fabrication.
APPLIED SURFACE SCIENCE
(2023)
Article
Physics, Multidisciplinary
Yasen Hou, Fabrizio Nichele, Hang Chi, Alessandro Lodesani, Yingying Wu, Markus F. Ritter, Daniel Z. Haxell, Margarita Davydova, Stefan Ilic, Ourania Glezakou-Elbert, Amith Varambally, Sebastian Bergeret, Akashdeep Kamra, Liang Fu, Patrick A. Lee, Jagadeesh S. Moodera
Summary: The macroscopic coherence in superconductors allows for dissipationless supercurrents, which can have significant implications in emerging quantum technologies. By implementing unequal supercurrents in the forward and backward directions, the superconducting diode effect can be achieved, enabling unprecedented functionalities. Through experiments and theoretical modeling, we demonstrate the strong superconducting diode effect in conventional superconducting thin films, as well as its enhancement when interfacing with a ferromagnetic semiconductor.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Jiaming Zhao, Zhihe Wang
Summary: Fe1-xKxSe0.5Te0.5 (x = 0, 0.025, 0.05, 0.075, and 0.1) single crystals were grown by self-flux method. The effects of K-doping on various properties were investigated, including the length of c-axis, critical temperature, anisotropy, and critical current density. It was found that with the increase of K-doping content, the length of c-axis increased, the critical temperature initially rose and then fell, and the anisotropy decreased. At x = 0.075, a significant increase in critical current density was observed. The superconducting properties of Fe(0.925)K(0.075)Se(0.5)Te(0.5) were also thoroughly studied, including field-dependent pinning energy and temperature-dependent upper critical field. The results suggested a temperature-induced pinning mechanism from normal point pinning to normal surface pinning, with the involvement of twins. The temperature-dependent critical current density J(c)(T)=J(c)(0)(1-T/T-1)(n) was discussed, and the n-value was found to depend on different flux pinning regimes.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Physics, Applied
Sudhir Regmi, Zhong Li, K. C. Shambhu, Rabin Mahat, Ankur Rastogi, Ranjan Datta, Arunava Gupta
Summary: Epitaxial thin films of cobalt ferrite have been successfully grown on isostructural substrates using pulsed laser deposition. The films on ZnGa2O4 substrates are defect-free and under slight compressive strain, while the films on MgGa2O4 substrates show strain relaxation and defect formation.
APPLIED PHYSICS LETTERS
(2022)
Article
Multidisciplinary Sciences
Jin Yue, Yilikal Ayino, Tristan K. Truttmann, Maria N. Gastiasoro, Eylon Persky, Alex Khanukov, Dooyong Lee, Laxman R. Thoutam, Beena Kalisky, Rafael M. Fernandes, Vlad S. Pribiag, Bharat Jalan
Summary: Using hybrid MBE, high-quality SrTiO₃ films with low defect density were obtained, and their transport properties were studied. The dominant influence of intraband scattering at the second Lifshitz transition was observed, along with the anomalous temperature dependence of the Hall scattering factor and carrier density due to the antiferrodistortive transition.
Article
Multidisciplinary Sciences
Wenzheng Wei, Dung Vu, Zhan Zhang, Frederick J. J. Walker, Charles H. H. Ahn
Summary: We report on the superconductivity in Nd1-xEuxNiO2, where Eu is used as a 4f dopant. By employing an in situ molecular beam epitaxy reduction process, we achieve the superconducting phase, providing an alternative method to induce superconductivity in infinite-layer nickelates compared to the ex situ CaH2 reduction process. The Nd1-xEuxNiO2 samples exhibit a step-terrace surface structure, have a T-c onset of 21 K at x = 0.25, and show a large upper critical field possibly due to Eu 4f doping.
Article
Physics, Applied
D. Torsello, R. Gerbaldo, L. Gozzelino, F. Laviano, A. Takahashi, A. Park, S. Pyon, A. Ichinose, T. Tamegai, G. Ghigo
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2020)
Article
Nanoscience & Nanotechnology
Ataru Ichinose, Tsuyoshi Hamada, Keisuke Ota, Iwao Kawayama, Toshiya Doi
Article
Materials Science, Multidisciplinary
Sunseng Pyon, Yuto Kobayashi, Ayumu Takahashi, Wenjie Li, Teng Wang, Gang Mu, Ataru Ichinose, Tadashi Kambara, Atsushi Yoshida, Tsuyoshi Tamegai
PHYSICAL REVIEW MATERIALS
(2020)
Article
Physics, Applied
Ataru Ichinose, Sunseng Pyon, Tsuyoshi Tamegai, Shigeyuki Ishida
Summary: CaKFe4As4 single crystals exhibit significant anisotropy in critical current density (J(C)), with planar defects originating from KFe2As2 step networks, and dark contrast regions observed in STEM result from local strain distributions caused by the substitution of Ca by K.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Akihiro Kikuchi, Yasuo Iijima, Shigeki Nimori, Masaru Yamamoto, Masahiko Kawano, Motoyoshi Kimura, Jun Nagamatsu, Masato Otsubo, Ataru Ichinose, Kiyosumi Tsuchiya
Summary: The study shows that the critical current density of Nb3Al wires increases with decreasing diameter, with the maximum Jc obtained on 30 m diameter wires. A 7-wire round cable and a 3rd bundle Rutherford cable have been successfully fabricated using these wires. Transport current tests showed no differences in Ic and n-values between different processes.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2021)
Article
Physics, Applied
Kiyosumi Tsuchiya, Xudong Wang, Shinji Fujita, Ataru Ichinose, Kyohei Yamada, Akio Terashima, Akihiro Kikuchi
Summary: The research investigates the development and commercialization of rare-earth barium copper oxide coated conductors, as well as the current-carrying capabilities of conductors doped with artificial pinning centers in high magnetic fields. The testing results show that conductors with artificial pinning centers have significantly higher critical current values under perpendicular fields and perform well under high magnetic fields.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Tomoya Horide, Ataru Ichinose, Fumiaki Tokura, Kaname Matsumoto
Summary: Nanocomposite films containing self-organized oxide nanocolumns were fabricated by pulsed laser deposition, showing the formation of Sr-Ti-O nanocolumns with a diameter of 2-5 nm and spacing <10 nm at specific deposition temperature and STO content. The morphology of nanocolumns in chalcogenide-oxide nanocomposites is expected to effectively influence the properties of chalcogenides.
Article
Chemistry, Physical
Sunseng Pyon, Soichi Taya, Yuto Kobayashi, Ayumu Takahashi, Wenjie Li, Toshihiro Taen, Teng Wang, Gang Mu, Hisashi Kitamura, Ataru Ichinose, Tsuyoshi Tamegai
Summary: The study investigates the critical current density and vortex pinning properties in single crystals of a novel iron-based superconductor KCa2Fe4As4F2, showing significant enhancement of performance after irradiation. Vortex dynamics in KCa2Fe4As4F2 are found to be similar to (Ba,K)Fe2As2 to some extent, but different from Li0.8Fe0.2OHFeSe.
Article
Chemistry, Physical
Giovanna Latronico, Saurabh Singh, Paolo Mele, Abdalla Darwish, Sergey Sarkisov, Sian Wei Pan, Yukihiro Kawamura, Chihiro Sekine, Takahiro Baba, Takao Mori, Tsunehiro Takeuchi, Ataru Ichinose, Simeon Wilson
Summary: The addition of 2% SnO2 significantly enhances the thermoelectric performance of AZO thin films on silica substrates, particularly in terms of power factor. Compared to typical AZO materials, the thermal conductivity is significantly reduced.
Article
Engineering, Electrical & Electronic
Shintaro Adachi, Ataru Ichinose, Fumiko Kimura, Shigeru Horii
Summary: This study examined the twinned microstructures of a magnetically biaxial aligned grain of DyBa2Cu3Oy using transmission electron microscopy (TEM). Planar views of the grain were obtained more easily through the use of biaxial aligned grain. The study revealed an inhomogeneous abundance ratio of two different types of domains, which suggested the presence of triaxial magnetic anisotropy at the grain level and its contribution to the biaxial alignment of RE123 grains under MRFs.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Physics, Applied
Tomoya Horide, Hiromu Katagiri, Ataru Ichinose, Kaname Matsumoto
Summary: The incorporation of different materials can control the phase formation and nanostructure of Fe(Te,Se) films, thus affecting their superconducting properties. Adding SrTiO3 to the films resulted in c-axis oriented structures and the formation of nanocomposite structures with increasing SrTiO3 content.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Mitsuhiro Muta, Suguru Nishikawa, Ataru Ichinose, Yukio Sato, Makoto Arita, Yoshifumi Ikoma, Masashi Mukaida
Summary: Preferred orientation and optical responses were investigated for BaBiO3 films grown by pulsed laser deposition. The films exhibited monoclinic symmetry I2/m and a (110) preferred orientation. The estimated optical bandgaps were around 2.3 eV for direct transition and 2.1 eV for indirect transition. The decay time of photoconductivity was found to be approximately 0.48 sec. The relationship between ultraviolet light-induced photoconductivity and film crystallinity was clarified, with high-quality crystalline BaBiO3 films exhibiting lower photoconductivity, contrary to TiO2 films.
Article
Physics, Applied
Tomoya Horide, Ataru Ichinose, Masashi Tanaka, Kaname Matsumoto
Summary: The control of nanostructure is crucial in both fundamental and technological aspects, as it determines various properties of superconductors such as vortex pinning. Although the nanostructure control in superconducting oxides is well-established, it remains challenging in iron-based superconductors due to the possibility of anionic substitution and non-stoichiometric anion. In this study, compositional inhomogeneity originating from phase separation was observed in Fe(Te,Se) films prepared through pulsed laser deposition. The compositional inhomogeneity was absent in films deposited at lower temperature, while high-temperature deposited films showed an anion distribution with the size of about 8 nm due to phase separation. The obtained structure is expected to function as an effective pinning center in high magnetic fields after further optimization, demonstrating a novel method of nanostructure control in Fe(Te,Se) different from nanocomposite formation in oxides.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Wenjie Li, Sunseng Pyon, Akiyoshi Yagi, Cheng Yu, Ryosuke Sakagami, Ataru Ichinose, Satoru Okayasu, Tsuyoshi Tamegai
Summary: Various peak effects induced by particle irradiations were investigated in 2H-NbSe2 single crystals. The peak effect induced by order-disorder transition of vortices was magnified by 3 MeV proton irradiation, while the peak effect in NbSe2 with splayed columnar defects showed a shift towards low fields with increasing splayed angle. Numerical calculations confirmed the mechanism behind the peak effect, and field dependence analysis revealed the formation of non-uniform J(c) flow. Coexistence of different peak effects was observed in symmetric splayed CD samples generated by Xe and Au ions, and a broad anomalous peak effect similar to iron-based superconductors was observed in Au-irradiated samples with small splay angle, which was suppressed by an externally applied magnetic field parallel to one of the splayed CDs.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
F. Nabeshima, Y. Kawai, N. Shikama, Y. Sakishita, A. Suter, T. Prokscha, S. E. Park, S. Komiya, A. Ichinose, T. Adachi, A. Maeda
Summary: Muon spin rotation/relaxation measurements were used to investigate the magnetic properties of FeSe1-xSx thin films on LaAlO3. The results show that S substitution induces magnetism at low temperatures in the films, with the anomaly temperature increasing and magnetic fluctuations being suppressed with increasing S content. The behavior of Tc is significantly different between the FeSe films under chemical pressure from S substitution compared to bulk FeSe under hydrostatic pressure.