Article
Materials Science, Multidisciplinary
Hanae Kijima-Aoki, Shigehiro Ohnuma, Nobukiyo Kobayashi, Hiroshi Masumoto
Summary: This research demonstrates a new structural optimization of cobalt-(barium fluoride) lateral nanogranular films, achieving independently variable direct current and alternating current tunneling effects in different directions. The lateral nanogranular films have potential applications as high-sensitivity magnetic sensors.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Hamed Sharifi Dehsari, Morteza Hassanpour Amiri, Kamal Asadi
Summary: Experimental realization of thin films with significant room-temperature magnetoelectric coupling coefficient α(ME) without an external DC magnetic field has been challenging. Here, large α(ME) of 750 +/- 30 mV Oe(-1) cm(-1) is achieved in multiferroic polymer nanocomposites (MPCs) thin films. The MPCs consist of PMMA-grafted cobalt-ferrite nanoparticles uniformly dispersed in piezoelectric polymer P(VDF-TrFE). Nanoparticle agglomeration is reduced by surface functionalization with PMMA, enabling the uniform dispersion of nanoparticles in submicrometer thin films. This research can promote the development of flexible and printable multiferroic electronic devices for sensing and memory applications.
Article
Chemistry, Multidisciplinary
Yuzhu Wang, Peng Wang, Hao Wang, Bingqian Xu, Hui Li, Mo Cheng, Wang Feng, Ruofan Du, Luying Song, Xia Wen, Xiaohui Li, Junbo Yang, Yao Cai, Jun He, Zhenxing Wang, Jianping Shi
Summary: An ingenious space-confined chemical vapor deposition strategy was used to synthesize atomically thin non-layered epsilon-Fe2O3 single crystals and revealed the room-temperature long-range ferrimagnetic order. Strong ferroelectricity and its switching behavior were discovered in atomically thin epsilon-Fe2O3, along with an anomalous thickness-dependent coercive voltage. The robust room-temperature magnetoelectric coupling was uncovered by controlling the magnetism with an electric field, demonstrating the multiferroic feature of atomically thin epsilon-Fe2O3. This work represents a substantial leap in the controllable synthesis of 2D multiferroics with robust magnetoelectric coupling, and also paves the way for practical applications in low-energy-consumption electric-writing/magnetic-reading devices.
ADVANCED MATERIALS
(2023)
Article
Materials Science, Ceramics
Mei Ying Liu, Tu Lai Sun, Ting Ting Gao, Zhi Ping Bian, Zhen Lin Luo, Xiao Qiang Liu, Xiang Ming Chen
Summary: This study enhances the ferroelectricity of SmFeO3 thin films by introducing a CaTiO3 blocking layer, and verifies the room-temperature ferroelectricity and magnetoelectric coupling effect.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
Temuujin Bayaraa, Yurong Yang, Meng Ye, L. Bellaiche
Summary: First-principles calculations were used to compute linear magnetoelectric coupling coefficients in epitaxial (001) Sr0.5Ba0.5MnO3 films, revealing a significant enhancement of different linear magnetoelectric elements in a strained-induced morphotropic phase boundary region. This enhancement is attributed to the behavior of dielectric susceptibility and is accurately explained by a simple phenomenological model. This study offers a promising approach for designing single-phase multiferroic materials with colossal magnetoelectric conversion.
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
Engineering, Electrical & Electronic
M. Manjula Devi, Anitha Anand, R. K. Veena, V. S. Veena, K. Nandakumar, S. Sagar
Summary: This study systematically investigates the room temperature magnetoelectric properties of lead-free Bi0.9La0.1FeO3 and La0.7Sr0.3MnO3 composites synthesized via a solid-state reaction route. The addition of LSMO to the BLFO samples enhances magnetization values and increases the magnetoelectric coupling coefficient, showing potential applications in low power consuming memory devices and sensors.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Materials Science, Composites
Yutie Gong, Zhenzhen Li, Hairong Li, Weijie Zhou, Jiayu Zhao, Xianglin Pei, Ming Jiang, Wei Gong
Summary: A general solution is demonstrated to attain an excellent cost/performance balance in room-temperature dielectric switching materials by mixing ionic liquids with polyethylene glycol. The resulting all-organic composite exhibits ultrahigh dielectric switching properties, high retention rate, wide thermal hysteresis loop, and tunable transition temperature. It also overcomes the conflict between dielectric switching properties and cost.
COMPOSITES COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Parminder Singh, Radhapiyari Laishram, Puneet Sharma, Jayant Kolte
Summary: The preparation and characteristics of BNT and NFO composite ceramics were investigated, revealing the optimum leakage current density and giant magnetocapacitance effect at certain NFO content.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Nanoscience & Nanotechnology
Jun Utsumi, Ryo Takigawa
Summary: The study focused on surface activated bonding (SAB) of Al2O3 films deposited by chemical vapor deposition at room temperature under short-time activated conditions. The crystallinity of Al2O3 film affects its bonding properties, and the surface energy for bonding of Al2O3 film/sapphire is higher compared to other bondings.
SCRIPTA MATERIALIA
(2021)
Article
Chemistry, Multidisciplinary
Bayan A. Kurbanova, Gauhar K. Mussabek, Viktor Y. Timoshenko, Vladimir Lysenko, Zhandos N. Utegulov
Summary: The study investigates the photothermal and heat conductive properties of nanogranular silicon films synthesized by evaporating colloidal droplets of crystalline silicon nanoparticles. Simulations and experiments show that the phase transition in these films is influenced by factors such as film thickness and substrate material, and the films have low thermal conductivity due to their voided topology and weak interface bonding.
Article
Chemistry, Physical
Satish Yadav, Mohit Chandra, R. Rawat, Ashish Khandelwal, L. S. Sharath Chandra, R. J. Choudhary, Vasant Sathe, A. K. Sinha, Kiran Singh
Summary: Co4Nb2O9 (CNO) is an interesting magnetoelectric material, and in this study, comprehensive temperature-dependent properties including structural, phonon, dielectric, and magnetic aspects were reported. The results show that CNO exhibits dielectric transition and magnetoelastic coupling at the antiferromagnetic ordering temperature (T-N).
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Physics, Applied
V. M. Andrade, N. R. Checca, V. G. de Paula, K. R. Pirota, A. L. Rossi, F. Garcia, A. Vovk, S. A. Bunyaev, G. N. Kakazei
Summary: In this study, Fe2CrAl Heusler nanoparticles with good crystallographic features were obtained using pulsed laser deposition technique. The structural, morphological, and magnetic properties of these nanoparticles were investigated, revealing slightly off-stoichiometric grains with two distinct morphologies. The magnetic behavior was found to be influenced by chemical disorder and inhomogeneity. The nanoparticles exhibited a superparamagnetic behavior and a Gilbert damping comparable to standard materials used in magnonics applications. The complex magnetostructural coupling in the nanoparticle system was discussed in comparison with the stoichiometric Fe2CrAl bulk target behavior.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Xianming Ren, Yemei Han, Xuegang Chen, Yi Fu, Fang Wang, Kai Hu, Zheng Sun, Kailiang Zhang
Summary: This study reports a novel single-phase magnetoelectric film that exhibits switchable polarization and magnetization, allowing for electric field control of magnetism. By substituting ions in the spinel sublattices, local distortions and electric fields are induced, modulating the superexchange interactions between magnetic ions and resulting in ferroelectricity and magnetoelectric effects.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Miquel Lopez-Suarez, Claudio Melis, Luciano Colombo, Walter Tarantino
Summary: Cluster-assembled metallic films exhibit interesting electrical properties both near and well above the percolation threshold, with correct estimation of conductivity being crucial. A procedure based on atomically informed mesoscopic models and ab initio estimates is developed to accurately reconstruct the conductivity of nanogranular gold films, capturing their nonmonotonic behavior as a function of film thickness.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Physics, Applied
Y. Tsutsumi, S. Maekawa
Summary: The coupling of spin angular momentum and mechanical rotation in liquid helium-3 generates a nuclear spin current through the Stern-Gerlach effect. The effective field gradient, estimated quantitatively based on the microscopic Boltzmann equation, is large enough to be detected in NMR measurements. This study demonstrates the potential of utilizing the spin-rotation coupling for controlling and detecting spin currents in liquid helium-3.
JOURNAL OF LOW TEMPERATURE PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Hideki Matsuoka, Stewart Edward Barnes, Jun'ichi Ieda, Sadamichi Maekawa, Mohammad Saeed Bahramy, Bruno Kenichi Saika, Yukiharu Takeda, Hiroki Wadati, Yue Wang, Satoshi Yoshida, Kyoko Ishizaka, Yoshihiro Iwasa, Masaki Nakano
Summary: This research presents strong out-of-plane magnetic anisotropy at the interface between two different vdW materials, and proposes a simple model to explain the observations. These results demonstrate a new magnetic proximity effect at the vdW interface, expanding the horizons of emergent phenomena achievable in vdW heterostructures.
Article
Physics, Multidisciplinary
Florian Lange, Satoshi Ejima, Junji Fujimoto, Tomonori Shirakawa, Holger Fehske, Seiji Yunoki, Sadamichi Maekawa
Summary: Using unbiased large-scale time-dependent density-matrix renormalization-group simulations, we have demonstrated the generation of a charge-current vortex via spin injection in the Rashba system. The spin current is polarized perpendicular to the system plane and injected from an attached antiferromagnetic spin chain. We discuss the conversion between spin and orbital angular momentum in the current vortex and predict the electromagnetic field accompanying the vortex for possible future experiments.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Applied
Michiyasu Mori, Sadamichi Maekawa
Summary: The study investigates a superconducting quantum interference device (SQUID) with 0- and pi-Josephson junctions (JJs), known as pi-SQUID, using the resistively shunted junction model. It demonstrates that the pi-SQUID exhibits half-integer Shapiro steps (SS) under microwave irradiation, making it a potential pi-qubit with spontaneous loop currents. The equivalence of 0- and pi-JJs is crucial for achieving the half-integer SS and realizing the pi-qubit.
APPLIED PHYSICS EXPRESS
(2021)
Article
Physics, Multidisciplinary
Hiroyuki Chudo, Masaki Imai, Mamoru Matsuo, Sadamichi Maekawa, Eiji Saitoh
Summary: The study demonstrates the observation of the angular momentum compensation temperature (TA) in ferrimagnets, determining it to be 240K in the Ho3Fe5O12 system. The increase of TA with Dy content is shown, with Ho1.5Dy1.5Fe5O12 corresponding to room temperature. Fe-57-NMR measurements are used to explore domain wall dynamics in HoIG, revealing an enhancement of NMR signal at TA due to increased domain-wall mobility.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2021)
Article
Nanoscience & Nanotechnology
Junji Fujimoto, Florian Lange, Satoshi Ejima, Tomonori Shirakawa, Holger Fehske, Seiji Yunoki, Sadamichi Maekawa
Summary: By utilizing response theory, the paper calculates the charge current vortex generated by spin pumping at a point-like contact in a system with Rashba spin-orbit coupling. The oscillatory behavior of the charge current as a function of distance from the spin pumping source is observed, which is supported by numerical simulations. The introduction of the SOC Hamiltonian on the lattice as the generator of the spin current is a significant aspect of their calculations.
Article
Engineering, Electrical & Electronic
Junji Fujimoto, Hiroshi Funaki, Wataru Koshibae, Mamoru Matsuo, Sadamichi Maekawa
Summary: Motivated by a recent experiment, this study examines the interaction between electric current vorticity and localized spins in FeGe devices, revealing three effects: the induction of an effective Zeeman field, a vorticity-induced Dzyaloshinskii-Moriya interaction, and a spin current driven by the vorticity gradient. These findings open up a new path for designing magnetic textures using structural settings.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Multidisciplinary Sciences
Jianyu Zhang, Mingfeng Chen, Jilei Chen, Kei Yamamoto, Hanchen Wang, Mohammad Hamdi, Yuanwei Sun, Kai Wagner, Wenqing He, Yu Zhang, Ji Ma, Peng Gao, Xiufeng Han, Dapeng Yu, Patrick Maletinsky, Jean-Philippe Ansermet, Sadamichi Maekawa, Dirk Grundler, Ce-Wen Nan, Haiming Yu
Summary: In multiferroic heterostructures, researchers have demonstrated a millimeter-long magnon decay length, solving a long-standing issue in metallic magnets. This magnon transport method shows potential for low-power computation.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Applied
J. Puebla, Y. Hwang, S. Maekawa, Y. Otani
Summary: Surface acoustic waves (SAWs) are elastic waves propagating on the surface of solids with the amplitude decaying into the solid. SAWs can manipulate the magnetization states by magnetostriction and magnetoelastic effects. This review discusses the characteristics of SAW devices and their interaction with the magnetization in thin films.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Kei Yamamoto, Mingran Xu, Jorge Puebla, Yoshichika Otani, Sadamichi Maekawa
Summary: In this paper, a theoretical description of magnon-phonon interactions in multilayer structures containing a ferromagnetic thin film is presented. The formalism takes into account external magnetic fields in arbitrary directions and various types of acoustic waves, including Rayleigh and Love surface modes. By paying attention to the spatial profile of acoustic wave modes and deriving analytical expressions for effective coupling coefficients, the study successfully reproduces a strongly anisotropic and non-reciprocal linewidth observed in recent experiments of acoustic ferromagnetic resonance.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Physics, Multidisciplinary
Hakuto Suzuki, Guoqiang Zhao, Jun Okamoto, Shoya Sakamoto, Zhi-Yin Chen, Yosuke Nonaka, Goro Shibata, Kan Zhao, Bijuan Chen, Wen-Bin Wu, Fan-Hsiu Chang, Hong-Ji Lin, Chien-Te Chen, Arata Tanaka, Masaki Kobayashi, Bo Gu, Sadamichi Maekawa, Yasutomo J. Uemura, Changqing Jin, Di-Jing Huang, Atsushi Fujimori
Summary: The magnetic properties and electronic excitations of Ba1-xKx(Zn1-yMny)2As2, a new diluted magnetic semiconductor, were studied using x-ray magnetic circular dichroism (XMCD) and resonant inelastic x-ray scattering (RIXS) techniques. The findings revealed that Mn atoms are in a high-spin configuration of d5, but the net spin moment is reduced due to the presence of competing ferromagnetic and antiferromagnetic interactions between Mn ions. RIXS spectra showed broad peaks originating from d-d crystal field excitations of Mn ions. Comparison with Ga1-xMnxAs indicated that the ground state of Mn in Ba1-xKx(Zn1-yMny)2As2 consists of both charge-transferred electron configuration and pure configuration with free holes.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Materials Science, Multidisciplinary
Yunyan Yao, Ranran Cai, See-Hun Yang, Wenyu Xing, Yang Ma, Michiyasu Mori, Yuan Ji, Sadamichi Maekawa, Xin-Cheng Xie, Wei Han
Summary: This study reports the experimental observation of half-integer Shapiro steps in a strong ferromagnetic Josephson junction, showing robustness in a wide temperature range. The formation of these steps is attributed to the coexistence of 0 and pi states in the NiFe junction. This conclusion is supported by high-resolution transmission electron microscopy characterization of the junction materials.
Article
Materials Science, Multidisciplinary
Junji Fujimoto, Wataru Koshibae, Mamoru Matsuo, Sadamichi Maekawa
Summary: The research demonstrates a Dzyaloshinskii-Moriya interaction driven by electric current vorticity, allowing for control of magnetic skyrmion creation and annihilation without an external magnetic field. The direction of the current and structural settings offer different possibilities for studying magnetic textures.
Article
Materials Science, Multidisciplinary
H. Chudo, M. Matsuo, S. Maekawa, E. Saitoh
Summary: Using the rotating nuclear quadrupole resonance (NQR) method, we observed the Barnett field, rotational Doppler effect, and Berry phase, and studied the different NQR line splittings in various setups. Analyzing these spectral structures allowed us to clarify the origins of NQR line splittings and discuss the relationship between rotational Doppler effect, Barnett field effect, and Berry phase. Additionally, we provided clear evidence of the differences between rotational Doppler effect and Barnett field, and the equivalence of Barnett field and Berry phase.
Article
Engineering, Electrical & Electronic
Shoya Sakamoto, Guoqiang Zhao, Goro Shibata, Zheng Deng, Kan Zhao, Xiancheng Wang, Yosuke Nonaka, Keisuke Ikeda, Zhendong Chi, Yuxuan Wan, Masahiro Suzuki, Tsuneharu Koide, Arata Tanaka, Sadamichi Maekawa, Yasutomo J. Uemura, Changqing Jin, Atsushi Fujimori
Summary: The study investigates the perpendicular magnetic anisotropy of a layered ferromagnetic semiconductor using angle-dependent X-ray magnetic circular dichroism measurements. The large magnetic anisotropy is attributed to the anisotropic distribution of Mn 3d electrons and the lifting of degeneracy of p-d(xz), d(yz) hybridized states.
ACS APPLIED ELECTRONIC MATERIALS
(2021)