Article
Chemistry, Physical
Javier Blasco, Gloria Subias, Jose Luis Garcia-Munoz, Francois Fauth, Joaquin Garcia
Summary: In this paper, a complete structural study of the YBaMn2O6 compound with successive phase transitions is conducted, revealing distinct structural features and arrangements of Mn sites as well as increasing charge differences. The compound undergoes three consecutive phase transitions, with the emergence of new structural characteristics and increased charge segregation, indicating specific and unique properties.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Inorganic & Nuclear
S. Yamada, H. Sagayama, M. Yamazaki, H. Aoki, K. Sugimoto, T. Arima
Summary: The study systematically investigates the antiferromagnetic and charge ordering phase transitions in double-perovskite manganite compounds. It reveals interesting phenomena such as temperature dependence, cell doubling, and asymmetric electron distribution.
JOURNAL OF SOLID STATE CHEMISTRY
(2022)
Article
Materials Science, Multidisciplinary
G. Subias, J. Blasco, V. Cuartero, S. Lafuerza, L. Simonelli, G. Gorni, M. Castro, J. Garcia
Summary: We investigated the temperature dependence of Mn local structure in A-site ordered RBaMn2O6 perovskites and their disordered counterparts R0.5Ba0.5MnO3 using XES and XAS. The results show that the MnO6 octahedron in LaBaMn2O6 remains regular at all temperatures, while a local distortion develops with decreasing R ionic radius in the ordered samples NdBaMn2O6, SmBaMn2O6, and YBaMn2O6. Charge segregation between nonequivalent Mn sites is confirmed in the polar phase of Sm and Y ordered samples. The study suggests a displacive mechanism for the charge-localization and polar transitions in Nd and Sm ordered samples, while a combination of displacive and order-disorder contributions is revealed for YBaMn2O6.
Article
Chemistry, Multidisciplinary
Rea Divina Mero, Kirari Ogawa, Shigeki Yamada, Hsiang-Lin Liu
Summary: The double perovskite YBaMn2O6 exhibits complex structural, magnetic, and charge/orbital ordering phase transitions. The correlation between temperature-dependent optical response and phase transitions was investigated through spectroscopic ellipsometry and Raman scattering spectroscopy. Changes in phonon modes and intensity at temperatures <200 K were related to charge ordering and magnetic order-induced changes.
Article
Materials Science, Multidisciplinary
J. Blasco, G. Subias, J. L. Garcia Munoz, F. Fauth, M. C. Sanchez, J. Garcia
Summary: In this study, the charge-orbital ordering and magnetic phase transitions in A-site ordered SmBaMn2O6 perovskite were investigated using synchrotron radiation x-ray powder diffraction and symmetry-adapted modes analysis. Successive phase transitions in charge, spin, and lattice degrees of freedom were observed with decreasing temperature. The two charge-ordered phases show differences in their stacking sequence along the c axis, leading to controversy in the literature.
Article
Chemistry, Inorganic & Nuclear
Alexei A. Belik, Dmitry D. Khalyavin, Yoshitaka Matsushita, Kazunari Yamaura
Summary: A new member of A-site columnar-ordered A(2)A'A'' B4O12 quadruple perovskites Y2CuGaMn4O12 prepared by a high-pressure, high-temperature method exhibits long-range ferrimagnetic order and anisotropic thermal expansion. The Cu2+ doping significantly changes the magnetic properties, affecting the ordering.
INORGANIC CHEMISTRY
(2022)
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
Materials Science, Multidisciplinary
Md Shafiqul Islam, Daisuke Morikawa, Shigeki Yamada, Bikas Aryal, Kenji Tsuda, Masami Terauchi
Summary: The space groups and crystal structures of A-site ordered NdBaMn2O6 perovskite were investigated at different temperatures, revealing different space groups and crystal structures. The low-temperature phase exhibited a fourfold periodicity.
Article
Chemistry, Multidisciplinary
Xiaofan Shen, Fan Wang, Xiaomei Lu, Junting Zhang
Summary: We demonstrate the coexistence and coupling of ferroelectricity and ferromagnetism in designed A-site ordered perovskite oxide monolayers. The Mn-based monolayers exhibit robust ferromagnetism, while some monolayers tend to form E-type spin order. The feasibility of controlling the direction of magnetization by electric field in the monolayer limit of perovskites is demonstrated.
Article
Multidisciplinary Sciences
Jianfa Zhao, Jiacheng Gao, Wenmin Li, Yuting Qian, Xudong Shen, Xiao Wang, Xi Shen, Zhiwei Hu, Cheng Dong, Qingzhen Huang, Lipeng Cao, Zhi Li, Jun Zhang, Chongwen Ren, Lei Duan, Qingqing Liu, Richeng Yu, Yang Ren, Shih-Chang Weng, Hong-Ji Lin, Chien-Te Chen, Liu-Hao Tjeng, Youwen Long, Zheng Deng, Jinlong Zhu, Xiancheng Wang, Hongming Weng, Runze Yu, Martha Greenblatt, Changqing Jin
Summary: The A-site-ordered perovskite PbHg3Ti4O12 is the only known quadruple perovskite that undergoes a phase transition from a high-temperature centrosymmetric paraelectric phase to a low-temperature non-centrosymmetric ferroelectric phase under high pressure synthesis. It bridges the gap between simple ABO(3) perovskites and A-site-ordered AA'3Ti4O12 perovskites, exhibiting both displacive ferroelectricity and unique structural coordination.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Inorganic & Nuclear
Jianming Deng, Feifei Han, Bjorn Schwarz, Michael Knapp, Helmut Ehrenberg, Weibo Hua, Manuel Hinterstein, Guobao Li, Yun He, Jie Wang, Yuan Yuan, Laijun Liu
Summary: A new perovskite oxide semiconductor CaCu3Fe2Ta2O12 was synthesized with high-pressure and high-temperature method, exhibiting a quadruple perovskite structure with ordered A-sites and partially ordered B-sites. The compound shows antiferromagnetic coupling between Fe3+ spins and ferromagnetic coupling between Cu2+ spins, leading to spin ordering at around 150 K. The material has a high dielectric permittivity of approximately 2500 at room temperature, with two dielectric relaxations observed - Debye-like relaxation attributed to charge carriers trapped in oxygen vacancies at low temperatures, and Maxwell-Wagner polarization relaxation at high temperatures. Is is a new magnetic semiconductor with A-site ordering intercorrelated with second-order Jahn-Teller distortion, providing opportunities for designing novel perovskite oxides with attractive magnetic and dielectric properties.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Dovydas Karoblis, Orlando C. C. Stewart Jr, Priscilla Glaser, Salah Eddin El Jamal, Agne Kizalaite, Tomas Murauskas, Aleksej Zarkov, Aivaras Kareiva, Sarah L. L. Stoll
Summary: Rare-earth manganese pyrochlores (R2Mn2O7), frustrated magnetic materials previously accessed only by high-pressure and high-temperature synthesis, were successfully prepared using a simple molten salt method at ambient pressure. The synthetic procedure did not require high pressures, temperatures, or oxygen flow. The method's versatility was demonstrated by the preparation of a mixed rare-earth solid solution and phase-selectivity for yttrium manganese oxides.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Gohil S. Thakur, Walter Schnelle, Martin Jansen
Summary: The B-site ordered double perovskite Sr2CaOsO6 has been synthesized by a solid-state reaction under ambient pressure. The compound crystallizes in the monoclinic space group P2(1)/n and remains paramagnetic down to a temperature of 2 K. This finding is relevant for understanding high-temperature ferromagnetism and possible exotic ground states in frustrated magnetic systems.
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
(2023)
Review
Chemistry, Inorganic & Nuclear
Alexei A. Belik, Roger D. Johnson, Dmitry D. Khalyavin
Summary: Perovskite-structure AMnO(3) manganites have contributed to the development of various physical concepts, while A-site-ordered quadruple perovskite manganites AMn(7)O(12) exhibit rich physics beyond the canonical materials. Recent progress in understanding them has been achieved with the wider use of high-pressure synthesis techniques.
DALTON TRANSACTIONS
(2021)
Article
Energy & Fuels
Shodruz T. Umedov, Dhruba B. Khadka, Masatoshi Yanagida, Anastasia Grigorieva, Yasuhiro Shirai
Summary: This study investigated the effects of A-site tailoring in Cs2SnI6 by adding monovalent cations such as Rb and Ag. The results showed that these additives could suppress CsI secondary phase and have a positive impact on opto-physical properties and device characteristics within a certain range.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2021)
Article
Instruments & Instrumentation
G. Simutis, A. Bollhalder, M. Zolliker, J. Kuespert, Q. Wang, D. Das, F. Van Leeuwen, O. Ivashko, O. Gutowski, J. Philippe, T. Kracht, P. Glaevecke, T. Adachi, M. Zimmermann, S. Van Petegem, H. Luetkens, Z. Guguchia, J. Chang, Y. Sassa, M. Bartkowiak, M. Janoschek
Summary: We propose an in situ uniaxial pressure device designed for small angle x-ray and neutron scattering experiments at low temperatures and high magnetic fields. The device uses a rod with an integrated transducer to transmit force to the sample, allowing forces of up to 200 N in both compressive and tensile configurations. It can be operated in a continuous-pressure mode with feedback control while the temperature is changing. The device is compatible with various instruments and cryostats through simple and exchangeable adapters, and it supports rapid sample changes with multiple sample holders.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Multidisciplinary Sciences
Z. Guguchia, C. Mielke, D. Das, R. Gupta, J. -X. Yin, H. Liu, Q. Yin, M. H. Christensen, Z. Tu, C. Gong, N. Shumiya, Md Shafayat Hossain, Ts Gamsakhurdashvili, M. Elender, Pengcheng Dai, A. Amato, Y. Shi, H. C. Lei, R. M. Fernandes, M. Z. Hasan, H. Luetkens, R. Khasanov
Summary: In this study, pressure-tuned and ultra-low temperature muon spin spectroscopy was used to uncover the unconventional nature of superconductivity in RbV3Sb5 and KV3Sb5. It was found that at ambient pressure, time-reversal symmetry breaking charge order was observed in RbV3Sb5, and the superconducting state displayed a nodal energy gap and reduced superfluid density. Applying pressure suppressed the charge-order transitions, increased the superfluid density, and progressively evolved the superconducting state from nodal to nodeless. The optimal superconductivity state was found to break time-reversal symmetry. These results offer unique insights into the nature of the pairing state and highlight the tunable nodal kagome superconductivity competing with time-reversal symmetry-breaking charge order.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Tomohiko Nakajima, Tetsuo Tsuchiya
Summary: We synthesized MCNC film thermistors on aramid fibers using a photocrystallization technique with KrF laser irradiation. The resulting ultrafine-fiber thermistor showed good semiconducting behavior, rapid response time, and equivalent rise and drop rates, due to the small heat capacity of the fiber substrate. Thermal-transfer simulations demonstrated that the fiber thermistor outperformed sheet-type thermistors in detecting temperature variations of microscopic objects. These ultrafine MCNC fiber thermistors with rapid and accurate temperature responses have potential applications as microscopic temperature sensors.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Multidisciplinary Sciences
Rui-Ting Gao, Nhat Truong Nguyen, Tomohiko Nakajima, Jinlu He, Xianhu Liu, Xueyuan Zhang, Lei Wang, Limin Wu
Summary: Here we demonstrate a strategy to enhance the photoelectrochemical performance of the BiVO4 photoanode in neutral electrolyte by in situ forming a NiB layer through the addition of nickel and borate species. The NiB/BiVO4 photoanode shows a high photocurrent density of 6.0 mA cm-2 at 1.23 VRHE and a photostability over 600 hours. The addition of Ni2+ inhibits the dissolution of NiB and improves the charge transfer, while borate species act as a promoter for catalyst activity. The synergy effect of both species suppresses charge recombination and photocorrosion of BiVO4.
Article
Multidisciplinary Sciences
Yigui Zhong, Jinjin Liu, Xianxin Wu, Zurab Guguchia, J. -x. Yin, Akifumi Mine, Yongkai Li, Sahand Najafzadeh, Debarchan Das, Charles Mielke, Rustem Khasanov, Hubertus Luetkens, Takeshi Suzuki, Kecheng Liu, Xinloong Han, Takeshi Kondo, Jiangping Hu, Shik Shin, Zhiwei Wang, Xun Shi, Yugui Yao, Kozo Okazaki
Summary: The newly discovered kagome superconductors offer a promising platform to explore the interplay between band topology, electronic order, and lattice geometry. However, the nature of the superconducting ground state and the electron pairing symmetry in this system is still not well understood. In this study, we directly observed a nodeless and nearly isotropic superconducting gap in the momentum space of two different kagome superconductors using high-resolution and low-temperature angle-resolved photoemission spectroscopy. The unique properties of the superconducting gap are independent of charge order in the normal state. This comprehensive characterization provides essential information about the electron pairing symmetry in kagome superconductors and advances our understanding of superconductivity and intertwined electronic orders in quantum materials.
Article
Instruments & Instrumentation
Lars Gerchow, Sayani Biswas, Gianluca Janka, Carlos Vigo, Andreas Knecht, Stergiani Marina Vogiatzi, Narongrit Ritjoho, Thomas Prokscha, Hubertus Luetkens, Alex Amato
Summary: The pioneering work on Muon-induced x-ray emission (MIXE) technique was conducted at the Paul Scherrer Institute (PSI) in the 1980s for non-destructive assessment of elemental compositions. In recent years, this method has been improved and adopted at many muon facilities worldwide. The GermanIum Array for Non-destructive Testing (GIANT) setup at PSI is a dedicated MIXE spectrometer that offers excellent performance and has been used for various applications such as archaeological research and collaboration with the industry.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Chemistry, Physical
Tomohiko Nakajima, Yuuki Kitanaka
Summary: High-quality, uniaxially oriented, and flexible PbZr0.52Ti0.48O3 (PZT) films were fabricated on flexible RbLaNb2O7/BaTiO3 (RLNO/BTO)-coated polyimide (PI) substrates using a photo-assisted chemical solution deposition (PCSD) process. The RLNO seed layer, grown only at 40 mJ center dot cm(-2) at 300 degrees C, played a crucial role in orienting the growth of the PZT film and suppressing micro-cracks. This is the first demonstration of PZT films crystallized directly on flexible substrates.
Article
Humanities, Multidisciplinary
Sayani Biswas, Isabel Megatli-Niebel, Lilian Raselli, Ronald Simke, Thomas Elias Cocolios, Nilesh Deokar, Matthias Elender, Lars Gerchow, Herbert Hess, Rustem Khasanov, Andreas Knecht, Hubertus Luetkens, Kazuhiko Ninomiya, Angela Papa, Thomas Prokscha, Peter Reiter, Akira Sato, Nathal Severijns, Toni Shiroka, Michael Seidlitz, Stergiani Marina Vogiatzi, Chennan Wang, Frederik Wauters, Nigel Warr, Alex Amato
Summary: A knob bow fibula of the Leutkirch type was excavated in 2018 in Switzerland and analyzed for its elemental composition. The fibula was made of bronze and consisted of two workpieces, with one being cast bronze and the other being forged bronze. The main elements in the fibula were copper, zinc, tin, and lead.
Article
Chemistry, Multidisciplinary
Ziga Gosar, Tina Arh, Kevin Jaksetic, Andrej Zorko, Wenhao Liu, Hanlin Wu, Chennan Wang, Hubertus Luetkens, Bing Lv, Denis Arcon
Summary: Quasi-one-dimensional electron systems exhibit instability towards long-range ordered phases at low temperatures. In this study, muon spin rotation and relaxation (& mu;SR) were used to investigate the superconducting state in Rb2Mo3As3, which has one of the highest critical temperatures Tc = 10.4 K among quasi-one-dimensional superconductors. The results show stronger damping below Tc due to the formation of a vortex lattice. Comparison of different models suggests that the s-wave scenario provides the best fit, but with an anomalously small superconducting gap ⠁0/Tc ratio of 2 ⠁0/kBTc = 2.74(1). However, the nodal p-wave or d-wave scenarios cannot be ruled out based on slightly worse fits, yielding more realistic ratios of 2 ⠁0/kBTc = 3.50(2) and 2 ⠁0/kBTc = 4.08(1), respectively.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2023)
Review
Materials Science, Multidisciplinary
Z. Guguchia, R. Khasanov, H. Luetkens
Summary: Kagome lattices are intriguing and rich platforms for studying the intertwining of topology, electron correlation, and magnetism. In this review, recent experimental progress on superconductivity and magnetic fingerprints of charge order in kagome-lattice systems is discussed. The systems include AV(3)Sb(5), LaRu3Si2, and CeRu2, which exhibit unique properties such as time-reversal symmetry-breaking charge ordered state, unconventional superconductivity, and rare nodeless magnetic kagome superconductivity.
NPJ QUANTUM MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
J. M. Law, H. Luetkens, G. Pascua, Th. Hansen, R. Glaum, Z. -s. Wang, J. Wosnitza, R. K. Kremer
Summary: We investigated the long-range magnetic ordering in the linear-chain spin S = 1/2 compound CuCrO4 using powder neutron diffraction and muon-spin rotation measurements. Both methods confirmed the presence of incommensurate long-range antiferromagnetic ordering below 8.5(3) K. The magnetic structure was determined based on neutron powder diffraction patterns, with a propagation vector iota = (0, 0, 0.546(1)). The Cu moments form a helicoidal spiral with an easy plane coinciding with the equatorial planes of the Jahn-Teller elongated CuO6 octahedra. The multiferroic phase was found to extend up to similar to 25 T, beyond which a new phase appeared. The magnetic moment is expected to fully saturate at fields much higher than 60 T.
Proceedings Paper
Physics, Applied
Fabian Hotz, Tina Arh, Zurab Guguchia, Debarchan Das, Chennan Wang, Matjaz Gomilsek, Andrej Zorko, Hubertus Luetkens
Summary: Muon Knight-shift measurements are challenging due to the lack of a direct method for measuring the applied external magnetic field. We propose a solution to this problem and suggest a suitable sample mounting and correcting scheme. This allows us to accurately determine the Knight-shift values even in extreme sample environments where separate measurements of the magnetic field are not feasible or practical using NMR or additional mu SR.
15TH INTERNATIONAL CONFERENCE ON MUON SPIN ROTATION, RELAXATION AND RESONANCE
(2023)
Article
Materials Science, Multidisciplinary
V. K. Anand, D. T. Adroja, C. Ritter, Debarchan Das, Harikrishnan S. Nair, A. Bhattacharyya, Leandro Liborio, Simone Sturniolo, F. L. Pratt, Duc Le, G. Andre, Hubertus Luetkens, A. D. Hillier, Z. Hossain
Summary: We present results of muon spin relaxation (mu SR), neutron powder diffraction (NPD), and inelastic neutron scattering (INS) investigations on polycrystalline Pr2Pd3Ge5. The polycrystalline compound exhibits two antiferromagnetic transitions, which were confirmed by heat capacity measurements. Magnetic Bragg peaks were observed in the magnetically ordered state, and the magnetic structure was determined to be a canted antiferromagnetic structure of ordered Pr3+ moments. In the paramagnetic state, crystal electric field (CEF) excitations were observed through INS, and a CEF level scheme was derived through analysis.
Article
Materials Science, Multidisciplinary
Chanhyeon Lee, Suheon Lee, Youngsu Choi, C. Wang, H. Luetkens, T. Shiroka, Zeehoon Jang, Young-Gui Yoon, Kwang-Yong Choi
Summary: We used various measurements, including magnetic susceptibility, muon-spin relaxation, and nuclear magnetic resonance, to study the spin dynamics of the quantum spin liquid candidate H3LiIr2O6. We identified two characteristic temperatures, Tg = 110 K and T* = 26 K, through analysis of the relaxation rates. Below Tg, there were distinct components of slower relaxation rate governed by gapped excitations and faster relaxation rate related to gapless excitations. We observed divergent magnetic susceptibility, power-law dependence of relaxation rate on temperature, and weakly activated behavior, indicating the coexistence of a disordered spin-liquid state and spin singlets with distributed gaps.
Article
Materials Science, Multidisciplinary
Vadim Grinenko, Rajib Sarkar, Shreenanda Ghosh, Debarchan Das, Zurab Guguchia, Hubertus Luetkens, Ilya Shipulin, Aline Ramires, Naoki Kikugawa, Yoshiteru Maeno, Kousuke Ishida, Clifford W. Hicks, Hans-Henning Klauss
Summary: Muon spin rotation/relaxation (μSR) and polar Kerr effect measurements provide evidence for a time-reversal symmetry breaking (TRSB) superconducting state in Sr2RuO4. However, the absence of a cusp in the superconducting transition temperature (Tc) vs stress and the absence of a resolvable specific heat anomaly at TRSB transition temperature (TTRSB) under uniaxial stress challenge a hypothesis of TRSB superconductivity. Recent μSR studies under pressure and with disorder indicate that the splitting between Tc and TTRSB occurs only when the structural tetragonal symmetry is broken. To further test such behavior, we measured Tc through susceptibility measurements and TTRSB through μSR, under uniaxial stress applied along a (110) lattice direction. We have obtained preliminary evidence for suppression of TTRSB below Tc, at a rate much higher than the suppression rate of Tc.
