Article
Multidisciplinary Sciences
Changmin Lee, Praveen Vir, Kaustuv Manna, Chandra Shekhar, J. E. Moore, M. A. Kastner, Claudia Felser, Joseph Orenstein
Summary: In this study, researchers discovered a phase transition within the domain walls of Co3Sn2S2, leading to a change in magnetization texture. They propose that this transition is a result of the compound's unique magnetocrystalline anisotropy. This research expands the traditional classification of domain walls and suggests new strategies for manipulating domain walls and their role in electron and spin transport.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
V. Fernandez Becerra, Mircea Trif, Timo Hyart
Summary: We study the properties of semiconducting nanowires with induced superconductivity and ferromagnetism, and find that spin pumping is quantized in the topologically nontrivial phase while charge pumping is not. In long topologically nontrivial nanowires, there is a one-to-one correspondence between quantized conductance, entropy change, and spin pumping. The observation of correlated and quantized peaks in conductance, entropy change, and spin pumping would provide strong evidence of Majorana zero modes.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Zijian Hong, Sujit Das, Christopher Nelson, Ajay Yadav, Yongjun Wu, Javier Junquera, Long-Qing Chen, Lane W. Martin, Ramamoorthy Ramesh
Summary: Controlling domain formation in ferroelectric materials at the nanoscale is crucial for exploring emergent phenomena and technological prospects. Polar vortices can play a similar role as ferroelectric domain walls, but with the ability to accommodate charged domains, making them reversible under an external applied field.
Article
Chemistry, Multidisciplinary
Ke Pei, Shanshan Liu, Liting Yang, Enze Zhang, Ruixuan Zhang, Chendi Yang, Linfeng Ai, Zihan Li, Faxian Xiu, Renchao Che
Summary: The study investigates the behavior of magnetic domains in the high-Curie temperature two-dimensional magnetic material Fe3GeTe2 under the drive of pulses, revealing complex dynamic processes due to multiple stable states of the magnetic structure. Cluster of domain walls are found to be more stable and move more synchronously under pulse current drive, which poses a challenge in race track memory devices and reinforces the potential of two-dimensional magnetic materials in application research.
Article
Chemistry, Multidisciplinary
Zhenghua Li, Bin Dong, Yangyang He, Aiying Chen, Xiang Li, Jing-Hua Tian, Chenglin Yan
Summary: Researchers have successfully realized a higher-order vortex network through a designed nanostructure and demonstrated its potential as a waveguide for spin waves. The experiment showed that spin waves can propagate into the network through nanochannels formed by Bloch-Neel-type domain walls, with a propagation decay length of several micrometers, paving the way for the development of low-energy, reprogrammable, and miniaturized magnonic devices.
Article
Physics, Multidisciplinary
N. Jiang, Y. Nii, H. Arisawa, E. Saitoh, J. Ohe, Y. Onose
Summary: Chirality in a helimagnetic structure is determined by the direction of magnetic moment rotation, and this information persists even after transitioning to a high-temperature ferromagnetic phase. Study on the 2nd harmonic resistivity rho(2f) reveals insights into chirality characteristics under different magnetic states, with the chirality memory effect possibly originating from ferromagnetic domain walls.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Haiming Yu, Jilei Chen, Vincent Cros, Paolo Bortolotti, Hanchen Wang, Chenyang Guo, Florian Brandl, Florian Heimbach, Xiufeng Han, Abdelmadjid Anane, Dirk Grundler
Summary: Electromagnetic metasurfaces, created by arranging elements with dimensions below the wavelength, can modulate a material's response to electromagnetic waves. This study reports the use of ferromagnetic metasurfaces to manipulate the transmission of spin waves in thin ferrimagnetic insulators. The efficiency of the metasurface is demonstrated to be 98.5%, with potential applications in on-chip control of microwaves.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
David G. Hopkinson, Takehito Seki, Nicholas Clark, Runze Chen, Yichao Zou, Ayumi Kimura, Roman Gorbachev, Thomas Thomson, Naoya Shibata, Sarah J. Haigh
Summary: Investigation using differential phase contrast scanning transmission electron microscopy reveals that Fe3GeTe2 exhibits different magnetic domain structures at different temperatures, with the domains undergoing changes and eventually disappearing at Tc.
Article
Microbiology
Xinying Liu, David J. F. Walker, Stephen S. Nonnenmann, Dezhi Sun, Derek R. Lovley
Summary: Geobacter sulfurreducens serves as a model microbe for studying extracellular electron transfer in various biogeochemical cycles, bioelectrochemical applications, and microbial metal corrosion. Recent research has shown that electrically conductive pili (e-pili) are abundant filaments in G. sulfurreducens and are essential for long-range electron transport. These findings provide important insights into the role of e-pili in facilitating extracellular electron transfer processes.
Article
Physics, Applied
Bushra Hussain, Michael G. Cottam
Summary: A theoretical analysis is conducted for the quantized spin waves in single-layered ferromagnetic nanorings with interfacial Dzyaloshinski-Moriya interactions (DMI). The inclusion of DMI effects shifts the transition field value between vortex and onion states and significantly modifies the spin-wave frequencies, with the largest effects observed near the transition field.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
H. Yamaguchi, S. C. Furuya, S. Morota, S. Shimono, T. Kawakami, Y. Kusanose, Y. Shimura, K. Nakano, Y. Hosokoshi
Summary: We present a model compound for a mixed-spin ferromagnetic chain, designed based on organic radicals. The compound shows ferromagnetic behavior and exhibits a double-peak structure in its magnetic specific heat, indicating a phase transition. Quantum Monte Carlo calculations and modified spin-wave theory explain the observed characteristics.
Article
Materials Science, Multidisciplinary
Hee-Sung Han, Sooseok Lee, Min-Seung Jung, Namkyu Kim, Dae-Han Jung, Myeonghwan Kang, Hye-Jin Ok, Weilun Chao, Young-Sang Yu, Jung-Il Hong, Mi-Young Im, Ki-Suk Lee
Summary: This study demonstrates the effective tuning of oscillation modes using the vortex core structure, showcasing the potential application of spin structures in nanotechnology.
NPG ASIA MATERIALS
(2022)
Article
Multidisciplinary Sciences
Quentin Stern, Samuel Francois Cousin, Frederic Mentink-Vigier, Arthur Cesar Pinon, Stuart James Elliott, Olivier Cala, Sami Jannin
Summary: Dynamic nuclear polarization is a widely used tool for enhancing the sensitivity of nuclear magnetic resonance spectroscopy and imaging, but its practical applicability is limited by the spin diffusion barrier, which hinders efficient polarization transfer between highly polarized nuclei and bulk nuclei.
Article
Materials Science, Multidisciplinary
Qingwei Fu, Like Liang, Wenqiang Wang, Liupeng Yang, Kaiyuan Zhou, Zishuang Li, Chunjie Yan, Liyuan Li, Haotian Li, Ronghua Liu
Summary: In this study, we experimentally observed the presence of net spin-orbit torques (SOT) in single conductive ferromagnet metal (HM) bilayers. In addition to the expected in-plane (IP) damping-like SOT, we also observed an unexpected out-of-plane (OOP) damping-like SOT. Using spin-torque ferromagnetic resonance technique, we measured the efficiencies of both IP and OOP SOT in pure Py. We propose that the IP SOT is primarily related to the Py bulk spin Hall effect, while the unconventional SOT is attributed to the out-of-plane polarized spin current generated from the nonequilibrium spin swapping effect. Furthermore, we found that these self-induced SOTs are also present in other commonly studied HM/FM multilayer systems, especially those with low conductivity.
Article
Materials Science, Multidisciplinary
Wenting Huang, Christophe Gatel, Zi-An Li, Gunther Richter
Summary: Fe and Co nano-whiskers and Co platelets were synthesized without using any template or catalyst via physical vapor deposition. The synthesized whiskers exhibited single crystal structures and magnetic single domain structures, while both FCC and HCP crystal structures were found in the Co whiskers. Vortex state was observed in a high symmetry platelet.
MATERIALS & DESIGN
(2021)
Article
Chemistry, Multidisciplinary
Tomohiro Hori, Naoya Kanazawa, Motoaki Hirayama, Kohei Fujiwara, Atsushi Tsukazaki, Masakazu Ichikawa, Masashi Kawasaki, Yoshinori Tokura
Summary: Strongly spin-orbit coupled states in metal interfaces, topological insulators, and 2D materials have great potential for spintronics. However, there are still challenges in integrating them into silicon electronics and dealing with the scarcity of constituent heavy elements. This study demonstrates robust spin-orbit coupling properties of a ferromagnetic topological surface state in FeSi and their controllability through hybridization with adjacent materials. The enhanced magnetic properties enable room-temperature magnetization switching, making it applicable for spin-orbit torque-based spintronic devices.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Xiuzhen Yu, Yizhou Liu, Konstantin V. Iakoubovskii, Kiyomi Nakajima, Naoya Kanazawa, Naoto Nagaosa, Yoshinori Tokura
Summary: 3D topological spin textures, called hopfions, have been theoretically predicted but not experimentally confirmed in helimagnetic systems. By using an external magnetic field and electric current, researchers successfully realized the existence of 3D topological spin textures, including fractional hopfions with non-zero topological index, in a skyrmion-hosting helimagnet FeGe. The dynamics of the expansion, contraction, and current-driven Hall motion of a bundle composed of a skyrmion and a fractional hopfion were controlled by microsecond current pulses. This research has demonstrated the novel electromagnetic properties of fractional hopfions and their ensembles in helimagnetic systems.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
Masao Nakamura, Ryuichi Namba, Takahiro Yasunami, Naoki Ogawa, Yoshinori Tokura, Masashi Kawasaki
Summary: This study identifies the two distinct quantization effects of spatially confined excitons in a 2D semiconductor PbI2, the enhanced binding energy under strong confinement and the center-of-mass quantization under weak confinement. The transition between these effects is revealed in high-quality epitaxial thin films, providing important insights for the development of optoelectronic functionalities of 2D materials.
APPLIED PHYSICS LETTERS
(2023)
Review
Physics, Applied
D. Bossini, D. M. Juraschek, R. M. Geilhufe, N. Nagaosa, A. Balatsky, M. Milanovic, V. V. Srdic, P. Senjug, E. Topic, D. Barisic, M. Rubcic, D. Pajic, T. Arima, M. Savoini, S. L. Johnson, C. S. Davies, A. Kirilyuk
Summary: Solid state compounds with multiple and coupled macroscopic orders, called multiferroics, pose challenges for modern condensed matter physics. Femtosecond laser pulses can manipulate spins and electric polarisation in these materials. This interdisciplinary problem requires contributions from materials science and condensed matter physics, both theoretically and experimentally.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Physics, Multidisciplinary
H. Takagi, R. Takagi, S. Minami, T. Nomoto, K. Ohishi, M. -t. Suzuki, Y. Yanagi, M. Hirayama, N. D. Khanh, K. Karube, H. Saito, D. Hashizume, R. Kiyanagi, Y. Tokura, R. Arita, T. Nakajima, S. Seki
Summary: The spontaneous topological Hall effect in triangular lattice compounds CoTa3S6 and CoNb3S6 is experimentally demonstrated, combining non-coplanar antiferromagnetic order with finite scalar spin chirality in the absence of a magnetic field. These compounds exhibit unconventionally large spontaneous Hall effects despite their small net magnetization, and the mechanism behind this phenomena is explained by the topological Hall effect associated with scalar spin chirality. The results suggest that the scalar spin chirality mechanism offers a promising route for the realization of a giant spontaneous Hall response in compensated antiferromagnets.
Article
Physics, Multidisciplinary
T. Nomura, X. -X. Zhang, R. Takagi, K. Karube, A. Kikkawa, Y. Taguchi, Y. Tokura, S. Zherlitsyn, Y. Kohama, S. Seki
Summary: The nonreciprocal acoustic properties of a room-temperature ferromagnet Co9Zn9Mn2 unveil the phonon magnetochiral effect close to room temperature. In contrast to the insulating Cu2OSeO3, the nonreciprocity in this metallic compound is enhanced at higher temperatures and observed up to 250 K. Ultrasound and microwave-spectroscopy experiments suggest that the magnitude of the phonon magnetochiral effect mostly depends on the Gilbert damping of Co9Zn9Mn2, which increases at low temperatures and hinders the magnon-phonon hybridization. It is also proposed that the phonon nonreciprocity can be further enhanced by engineering the magnon band of materials.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Kamil K. Kolincio, Max Hirschberger, Jan Masell, Taka-hisa Arima, Naoto Nagaosa, Yoshinori Tokura
Summary: Dynamical spin fluctuations in magnets can be influenced by lattice geometry, leading to chiral spin fluctuations and fluctuation-related transport anomalies. This study focuses on the crucial role of lattice geometry on chiral spin fluctuations and the quantum-mechanical phase of conduction electrons. Experimental results and Monte Carlo calculations suggest that lattices with dissimilar plaquettes exhibit the most promising Berry phase phenomena in paramagnets.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Keisuke Matsuura, Yo Nishizawa, Yuto Kinoshita, Takashi Kurumaji, Atsushi Miyake, Hiroshi Oike, Masashi Tokunaga, Yoshinori Tokura, Fumitaka Kagawa
Summary: This study investigates the phenomenon of hysteresis broadening in first-order phase transition materials using real-space magnetic imaging techniques. The researchers discover that the activated behavior of phase-front velocity during the transition explains the pronounced hysteresis broadening observed at low temperature. The findings provide a quantitative and comprehensive understanding of hysteresis broadening from a microscopic perspective.
COMMUNICATIONS MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Shunsuke Kitou, Yoshio Kaneko, Yuiga Nakamura, Kunihisa Sugimoto, Yusuke Nomura, Ryotaro Arita, Yoshinori Tokura, Hiroshi Sawa, Taka-hisa Arima
Summary: By performing core differential Fourier synthesis (CDFS) analysis of high-energy X-ray diffraction data, we directly observe the distribution state of Mo 4d orbital electrons in a pyrochlore-type oxide Nd2Mo2O7 at subangstrom resolution. The obtained valence electron density (VED) distribution confirms the Mo4+ 4d2 orbital state, and a dip in the radial profile indicates a node of the 4d wave function. The VED distribution around the Nd site is attributed to the hybridization of neighboring O 2p with Nd 6s/6p/5d orbitals and the anisotropic Nd3+ 4f3 electrons, which cannot be explained by simple j-j or LS coupling models. This study demonstrates the usefulness of CDFS analysis in investigating orbital states in crystalline materials.
Article
Materials Science, Multidisciplinary
Y. H. Zhuang, H. W. Liu, Y. H. Li, Y. M. Chang, T. Kurumaji, Y. Tokura, Y. M. Sheu
Summary: This study reveals the crucial role of crystal-field excitations involving spin-flip transitions in controlling switchable optomagnet effects in antiferromagnetic (Fe0.875Zn0.125)2Mo3O8. The photoinduced magnetization does not occur until the flipped spins are in excited states that frustrate the balanced spin moments, and it only starts to grow from a zero moment after the ultrashort pulses disappear. Through Kerr-effect microscopy and application of magnetic fields, the study distinguishes between photoinduced switchable magnetization and nonswitchable demagnetization. The experimental designs uncover essential factors for the development of antiferromagnetic memory devices using insulating oxides.
Article
Materials Science, Multidisciplinary
Jiwon Ju, Hiraku Saito, Takashi Kurumaji, Max Hirschberger, Akiko Kikkawa, Yasujiro Taguchi, Taka-hisa Arima, Yoshinori Tokura, Taro Nakajima
Summary: We investigated the magnetic structures of Gd2PdSi3, a centrosymmetric skyrmion material, using polarized neutron scattering. Our results confirmed the elliptic screw-type magnetic modulation in zero field with a propagation vector of (q, 0, 0). As the temperature increases, the system undergoes a magnetic phase transition while maintaining the incommensurate q-vector of (q, 0, 0). In the ground state, the system contains equal fractions of left-handed and right-handed screw-type orders, as expected from the centrosymmetric crystal structure.
Article
Materials Science, Multidisciplinary
Aki Kitaori, Jonathan S. White, Naoya Kanazawa, Victor Ukleev, Deepak Singh, Yuki Furukawa, Taka-hisa Arima, Naoto Nagaosa, Yoshinori Tokura
Summary: AC current-driven motions of spiral spin textures can create new electric fields and induce emergent electromagnetic induction effect, potentially realizing quantum inductor elements of micrometer size. Research on YMn6Sn6 helimagnet reveals the optimized conditions for emergent inductors beyond room temperature, achieved by modifying the magnetism through partial substitution of Y by Tb. The study demonstrates the control of both magnitude and sign of emergent electromagnetic inductance, and expands the range of potential candidate materials for emergent inductors.
Article
Materials Science, Multidisciplinary
Zheyuan Liu, Yusuke Araki, Taka-hisa Arima, Shinichi Itoh, Shinichiro Asai, Takatsugu Masuda
Summary: We performed an inelastic neutron-scattering experiment on a polycrystalline sample of a helimagnet Ni2InSbO6 to establish the spin Hamiltonian and observed well-defined spin-wave excitation below TN = 76 K with a band energy of 20 meV. The spectrum was reasonably reproduced using the linear spin-wave theory, which suggested honeycomb spin layers coupled along the stacking axis (the c axis). The proposed spin model successfully reproduced the soliton lattice generated by a magnetic field applied perpendicular to the c axis.
Article
Materials Science, Multidisciplinary
Masaki Gen, Rina Takagi, Yoshito Watanabe, Shunsuke Kitou, Hajime Sagayama, Naofumi Matsuyama, Yoshimitsu Kohama, Akihiko Ikeda, Yoshichika Onuki, Takashi Kurumaji, Taka-hisa Arima, Shinichiro Seki
Summary: We report a multi-axis dilatometric investigation of EuAl4 using a newly designed fiber-Bragg-grating technique complemented by a resonant x-ray scattering experiment, revealing anisotropic magnetostriction and magnetovolume effect associated with successive phase transitions. The rhombic and square SkL phases possess orthorhombic structural distortion of approximately 0.10% and 0.03% within the ab plane, respectively. The coupling between the spin system and lattice deformation is proposed to be essential for the structural instability in EuAl4, leading to a rich variety of topological spin textures and potential controllability of the SkL phases by uniaxial stress or pressure.
Article
Multidisciplinary Sciences
Kentaro Ueda, Tonghua Yu, Motoaki Hirayama, Ryo Kurokawa, Taro Nakajima, Hiraku Saito, Markus Kriener, Manabu Hoshino, Daisuke Hashizume, Taka-hisa Arima, Ryotaro Arita, Yoshinori Tokura
Summary: This study investigates the less studied half-Heusler alloy HoAuSn and demonstrates its transition into a Weyl semimetal state under a magnetic field, resulting in a significant decrease in resistance.
NATURE COMMUNICATIONS
(2023)
