Article
Chemistry, Multidisciplinary
Joscha Detzmeier, Kevin Koeniger, Tomasz Blachowicz, Andrea Ehrmann
Summary: Micromagnetic simulations on sputtered nanoparticles with different structures at zero temperature reveal that small deviations in systems due to random anisotropy orientations in different grains can lead to significant deviations in magnetization reversal processes and hysteresis loops, as well as distinctly asymmetric, horizontally shifted hysteresis loops in purely ferromagnetic nanoparticles.
Article
Chemistry, Multidisciplinary
Zhi Yang, Yuanyuan Chen, Weiqiang Liu, Yatao Wang, Yuqing Li, Dongtao Zhang, Qingmei Lu, Qiong Wu, Hongguo Zhang, Ming Yue
Summary: This study investigates the magnetic properties of exchange-coupled magnets, focusing on the effects of soft magnetic shell thickness and the aspect ratio of the hard magnetic core. It is found that the contributions of shape anisotropy to the magnetic properties are closely related to the thickness of the soft magnetic shell. Utilizing shape anisotropy can be an effective method to improve the magnetic performance of hard-soft exchange-coupled magnets.
Article
Physics, Multidisciplinary
Junaid Ul Ahsan, Harkirat Singh
Summary: In this study, we investigate the Exchange spring nano-bilayer with intermixing of high and low anisotropic moments at the interface and observe the unusual phenomenon of positive exchange bias. Our results show good reproducibility at different simulation temperatures. However, the temperature itself has a significant influence on the shift and width of the M-H loop. We further explain the importance of interface roughness in causing the shift of the Hysteresis loop in Ferromagnetic Hard/Soft nano bilayer systems.
Article
Nanoscience & Nanotechnology
Rafael Delgado-Garcia, Gabriel Rodriguez-Rodriguez, Jose M. Colino
Summary: The study introduces an optimized method for hysteresis loop averaging to reduce computational time for generating ensembles of magnetic nanoparticles, and demonstrates its effectiveness by comparing results with the Stoner-Wohlfarth hysteresis loop.
Article
Materials Science, Multidisciplinary
Namkyu Kim, Hee-Sung Han, Sooseok Lee, Min-Ji Kim, Dae-Han Jung, Myeonghawn Kang, Hyejin Ok, Youngkyun Son, Sukbin Lee, Ki-Suk Lee
Summary: The optimal condition for cylindrical core/shell hard-soft exchange-coupled magnetic nanostructures was explored through micromagnetic simulations, which showed that increasing the volume fraction of the soft magnet can enhance the demagnetizing field for achieving maximum energy product. Scaling up the nanostructure to bulk magnets with high BH can be achieved by forming an array of needle-shaped exchange-coupled cylinders. These findings have the potential to enable flexible design and scalable fabrication of exchange-coupled permanent magnets.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Chemistry, Physical
Xiangyi Liu, Bang Zhou, Bin Yuan, Zhongwu Liu
Summary: The magnetic properties of magnetic nanocomposites consisting of hard and soft magnetic phases depend on both intrinsic properties and the grain structure and volume ratio of the two phases. The grain size has a greater effect on the magnetic properties compared to the volume fraction of the hard magnetic phase. The effects of phase ratio and grain size on magnetic properties have been verified by experiments.
Article
Physics, Applied
O. T. L. Traistaru, P. Shyam, M. Christensen, S. P. Madsen
Summary: Permanent magnets based on ferrites are being studied as alternatives to rare-earth-based magnets due to their large crystalline anisotropy and the possibility of enhancing their saturation magnetization through exchange-coupling with a compatible soft magnetic material. The optimal conditions for maximum energy product in ferrite-based exchange-coupled magnets are determined using analytical calculations, finite element modeling, and experimental measurements. The results show that the alignment of hard grains and the amount of soft material play important roles in achieving high energy product.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Linhe Chen, Jing Cai, Wei Zhang
Summary: A study on the magnetic and thermodynamic behaviors of a ferromagnetic mixed-spin L1(0) nanoisland with a layered face center cubic structure using Monte Carlo simulation is conducted. The research focuses on the effects of anisotropies, exchange couplings, external magnetic field, and temperature on magnetization, susceptibility, internal energy, and hysteresis loop. It is found that the system exhibits triple saturation values, single hysteresis loops, and a double peak in the chi curve. The critical temperature and coercivity of the nanoisland depend on the exchange coupling and anisotropy.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Physics, Applied
Guiomar D. Soria, Cecilia Granados-Miralles, Anna Mandziak, Petra Jenus, Matilde Saura-Muzquiz, Mogens Christensen, Michael Foerster, Lucia Aballe, Jose F. Fernandez, Juan de la Figuera, Adrian Quesada
Summary: Composites of magnetically hard and soft phases play crucial roles in various applications, with the magnetic coupling between these phases influencing the macroscopic properties of the materials. Studies on a hard/soft bilayer system show significant differences in magnetization direction and magnetic domain patterns between the hard magnetic oxide and soft metallic overlayer. The results suggest that low degrees of exchange-coupling can prevent substantial softening of the composite and lead to the alignment of soft and hard magnetic moments.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Zhiming Dai, Kai Li, Zhenhua Wang, Wei Liu, Zhidong Zhang
Summary: Heavy rare-earth elements play an important role in the preparation of permanent magnets. This study investigates the phase composition and magnetization reversal mechanism of the Nd-Dy-Fe-B multicomponent system. It is found that substituting Nd with Dy suppresses certain phases and favors the formation of Nd2Fe14B phase. The study also reveals the influence of magnetic properties of grain boundaries on magnetization reversal.
Article
Materials Science, Multidisciplinary
Vivian M. Andrade, Sofia Caspani, Alejandro Rivelles, Sergey A. Bunyaev, Vladimir O. Golub, Joao P. Araujo, Gleb N. Kakazei, Celia T. Sousa, Mariana P. Proenca
Summary: This study demonstrates the feasibility of using Ni90Cu10/Fe20Co80 segmented NW as the writing element, where magnetic information is written by applying external magnetic fields. The results show that the soft segment (NiCu) induces a two-step reversal process of the hard segment (FeCo) when coupled, reducing its coercive and effective anisotropy fields. Micromagnetic simulations confirm the experimental observations.
MATERIALS & DESIGN
(2022)
Article
Physics, Applied
Syuta Honda, Yoshiaki Sonobe
Summary: This study proposes a new method for magnetization reversal on long pillars using both spin-orbit torque (SOT) and spin transfer torque, without the need for spin injection from a ferromagnet. Micromagnetic simulation confirms that this SOT-assisted method significantly reduces the reversal time and successfully reverses pillars with different characteristics. These findings are innovative and significant for practical applications.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Yuhui Wang, Ying Zheng, Ziyi Zhong, Zijun Wang, Yongfeng Liang, Pingping Wu
Summary: The magnetic properties of a core-shell type exchange coupled composite structure were studied using micromagnetic simulation. Switching loops with magnetic domain structure evolution were demonstrated and a switching type diagram was constructed. The effects of switching type and composite structure on coercivity and remanent magnetization were predicted and discussed. The core-shell type FePt/Fe composite structure film was found to have a significant advantage in designing high-density storage devices at the nanoscale.
Article
Biochemical Research Methods
Dan Lv, Jin-cheng Liu, Fan Zhang, De-zhi Zhang
Summary: The study investigated the magnetic behaviors of an antiferromagnetic/ferromagnetic mixed spin-5/2 and spin-3/2 Ising bilayer system in a time-dependent magnetic field using the Monte Carlo method. The analysis focused on magnetization, magnetic susceptibility, internal energy, and hysteresis loops, revealing how different physical parameters affect the critical temperature and observing a triple-loop hysteresis behavior.
JOURNAL OF MOLECULAR GRAPHICS & MODELLING
(2021)
Article
Physics, Multidisciplinary
Chun-lu Chang, Wei Wang, He Ma, Han Huang, Jin-cheng Liu, Rui-ze Geng
Summary: The study investigates the magnetic properties and magnetocaloric effect of a BiFeO3/Co bilayer with mixed-spin through Monte Carlo simulation, revealing that decreasing exchange coupling and increasing external magnetic fields can enhance the magnetic entropy change, adiabatic temperature change, and relative cooling power. The results also include hysteresis loops for different exchange couplings and temperatures.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2021)
Review
Materials Science, Multidisciplinary
Chu Ye, Lin-Lin Li, Yun Shu, Qian-Rui Li, Jing Xia, Zhi-Peng Hou, Yan Zhou, Xiao-Xi Liu, Yun-You Yang, Guo-Ping Zhao
Summary: This paper classifies and summarizes the various roles of rare metals in nucleating and manipulating skyrmions and other topological states. The materials covered include different types of crystals, layered systems, frustrated materials, antiferromagnets, ferrimagnets, and 2D materials. The review also discusses the impact of rare-earth permanent magnets on the dynamic behaviors of skyrmions.
Article
Physics, Applied
Yun Shu, Qianrui Li, Jing Xia, Ping Lai, Zhipeng Hou, Yonghong Zhao, Degang Zhang, Yan Zhou, Xiaoxi Liu, Guoping Zhao
Summary: This study computationally investigates the dynamics of isolated skyrmions in a ferromagnetic racetrack with enhanced and modified edge properties. Based on the racetrack design, various skyrmion logic gates and diodes are realized with significantly reduced driving current density. The study also explores the impact of temperature on the feasibility of the design.
APPLIED PHYSICS LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Wei Zhang, Tian Xun Huang, Michel Hehn, Gregory Malinowski, Maxime Verges, Julius Hohlfeld, Quentin Remy, Daniel Lacour, Xin Ran Wang, Guo Ping Zhao, Pierre Vallobra, Yong Xu, Stephane Mangin, Wei Sheng Zhao
Summary: Manipulating magnetic skyrmions using a femtosecond laser pulse has attracted attention due to their potential applications in energy-efficient information-storage devices. However, the mechanism for the creation of skyrmions induced by an fs laser is still unknown, and the challenge lies in understanding the transition from trivial to nontrivial magnetic states.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Physics, Applied
Gengxin Hu, Jia Luo, Junlin Wang, Xianyang Lu, Guoping Zhao, Yuan Liu, Jing Wu, Yongbing Xu
Summary: This work investigates the dynamic behavior of a current-driven bimeron in a nanotrack with voltage-controlled magnetic anisotropy (VCMA). The bimeron can display a diode-like unidirectional behavior by adjusting the profile of VCMA. The unidirectional behavior can be modulated by changing the driven current density and width of the VCMA region. The trajectory of the bimeron can be controlled by the periodic VCMA region, enhancing its stability and realizing a high-storage density bimeron-based information channel.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Physics, Multidisciplinary
Jing Xia, Xichao Zhang, Xiaoxi Liu, Yan Zhou, Motohiko Ezawa
Summary: We propose a skyrmion-based universal quantum computer that utilizes the helicity degree of freedom in frustrated magnets. It is shown that the quantum computation can be achieved based on nanoscale skyrmions in a magnetic bilayer system. Single-qubit gates are realized by controlling the electric field and spin current, while the two-qubit gate is achieved through Ising-type exchange coupling. The advantage of this mechanism is the elimination of the need for an external magnetic field. Our results may pave the way for universal quantum computation based on nanoscale topological spin textures.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Yuelei Zhao, Sheng Yang, Kai Wu, Shuang Li, Yang Gao, Hongyuan Hao, Xichao Zhang, Shouguo Wang, Qingfang Liu, Senfu Zhang, Zhiqin Chu, Johan Akerman, Yan Zhou
Summary: Synthetic antiferromagnetic (SAF) skyrmions, with high mobility and no skyrmion Hall effect, are emerging as novel information carriers. However, distinguishing SAF skyrmions from ferromagnetic ones using imaging techniques remains challenging. In this study, a universal identification method is proposed, and the motion of SAF skyrmions with suppressed skyrmion Hall effect is investigated. These findings will accelerate the realization of practical applications based on SAF skyrmions.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Xiuzhen Yu, Naoya Kanazawa, Xichao Zhang, Yoshio Takahashi, Konstantin V. Iakoubovskii, Kiyomi Nakajima, Toshiaki Tanigaki, Masahito Mochizuki, Yoshinori Tokura
Summary: This study reports the on-demand creation of multiple topological states in a helimagnet Fe0.5Co0.5Ge, including merons, antimerons, bimerons, and skyrmions, and demonstrates the transformations among these states through the application of magnetic fields and electric currents. These findings offer new insights into the manipulation of noncollinear spin textures and have potential applications in various fields.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Pengwei Dou, Jingyan Zhang, Yaqin Guo, Tao Zhu, Jia Luo, Guoping Zhao, He Huang, Guoqiang Yu, Yunchi Zhao, Jie Qi, Xiao Deng, Yuanbo Wang, Jialiang Li, Jianxin Shen, Xinqi Zheng, Yanfei Wu, Hongxin Yang, Baogen Shen, Shouguo Wang
Summary: This study reports on all electric-controlled magnetization switching in antiferromagnetic Co/Ir/Co trilayers with vertical magnetic imbalance. The switching polarity can be reversed by optimizing the Ir thickness. The polarized neutron reflection measurements reveal a canted noncollinear spin configuration in Co/Ir/Co trilayers, resulting from magnetic inhomogeneity. Micromagnetic simulations demonstrate asymmetric domain walls, caused by introduced imbalance magnetism, leading to deterministic magnetization switching in Co/Ir/Co trilayers.
Article
Multidisciplinary Sciences
Yuzhu Song, Tiankuo Xu, Guoping Zhao, Yuanji Xu, Zhicheng Zhong, Xinqi Zheng, Naike Shi, Chang Zhou, Yiqing Hao, Qingzhen Huang, Xianran Xing, Ying Zhang, Jun Chen
Summary: This study discovers a method to form high-density, spontaneous magnetic biskyrmions in ferrimagnets, which can exist within a wide temperature range. The strong connection between the atomic-scale ferrimagnetic structure and nanoscale magnetic domains is revealed, and the critical role of negative thermal expansion in generating biskyrmions is demonstrated.
Article
Engineering, Electrical & Electronic
Xuefeng Wu, Xu Li, Wenyu Kang, Xichao Zhang, Li Chen, Zhibai Zhong, Yan Zhou, Johan Akerman, Yaping Wu, Rong Zhang, Junyong Kang
Summary: Researchers have successfully constructed millimetre-scale meron lattices that are stable at room temperature and under zero magnetic field, which can be used as spin injectors in light-emitting diodes to provide 22.5% circularly polarized electroluminescence. These meron lattices are topological particle-like structures created in in-plane magnetized magnetic films. The lattices can transfer chirality from merons to electrons and then to photons, and it has been demonstrated that they can be used as spin injectors in nitride-based light-emitting diodes, producing circularly polarized electroluminescence at room temperature and under zero magnetic field.
NATURE ELECTRONICS
(2023)
Article
Materials Science, Multidisciplinary
Lan Bo, Rongzhi Zhao, Chenglong Hu, Xichao Zhang, Xuefeng Zhang, Masahito Mochizuki
Summary: In this study, a method for creating skyrmion bags in thin-film nanodisks is proposed, involving three steps: enlarging the size of the outer skyrmion using a vertical magnetic field, nucleating inner skyrmions at an off-center area through local current injection, and reconstructing the system through multiple interskyrmion potentials. As a result, skyrmion bags with a maximum topological charge of 40 can be created. Simulated Lorentz transmission electron microscopy images are provided to facilitate experimental demonstration. This research is expected to inspire relevant experiments in magnetic films and pave the way for potential spintronic applications based on skyrmion bags.
Article
Nanoscience & Nanotechnology
Zhang Wei, Huang Tian Xun, Michel Hehn, Gregory Malinowski, Maxime Verges, Julius Hohlfeld, Quentin Remy, Daniel Lacour, Wang Xin Ran, Zhao Guo Ping, Pierre Vallobra, Xu Yong, Stephane Mangin, Zhao Wei Sheng
Summary: This study demonstrates that the laser-magnetic phase transition process induced by femtosecond laser pulses can be mediated by the transient inplane magnetization state, resulting in the formation of topological skyrmions in real time and space domains. By combining experiments and micromagnetic simulations, a two-step process for creating skyrmions through laser pulse irradiation is proposed.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Sen Li, Qinyun Li, Jiancheng Liu, Nian Ran, Ping Lai, Laichuan Shen, Jing Xia, Linhua Xie, Yan Zhou, Guoping Zhao
Summary: In this study, a variational method is used to investigate rich topological spin textures in magnetic nanodisks, including skyrmions and skyrmionlike objects. The existence of these spin textures is theoretically studied in single-phase nanodisks and nanodisks with a core-shell structure. The phase diagrams of possible spin states are obtained for various Dzyaloshinskii-Moriya interaction (DMI) constants and disk diameters. The results suggest that skyrmions can be spontaneously generated in a core-shell nanodisk. The transitions of spin textures induced by spin currents in the nanodisk are also studied. This paper provides guidelines for the experimental realization of different topological spin textures in nanodisks with specific DMIs. The simple two-dimensional analytical method used in this paper can be applied to study the magnetic phase diagrams of thin films with interface-induced DMIs.
Article
Materials Science, Multidisciplinary
Xichao Zhang, Jing Xia, Xiaoxi Liu
Summary: In this study, the dynamics of particlelike skyrmions under compression and their lattice structural transitions are investigated. It is found that compression can induce a lattice structural transition of nanoscale skyrmions, leading to abrupt changes in skyrmion density. Additionally, the compression effect can cause a wave front and result in the collapse of some skyrmions, especially near the boundary between the driving and compressive regions.
Article
Materials Science, Multidisciplinary
Laichuan Shen, Jing Xia, Zehan Chen, Xiaoguang Li, Xichao Zhang, Oleg A. Tretiakov, Qiming Shao, Guoping Zhao, Xiaoxi Liu, Motohiko Ezawa, Yan Zhou
Summary: The study focuses on the nonreciprocal dynamics of asymmetrical ferrimagnetic bimerons induced by spin currents, showing that the bimerons can move at high speeds and do not exhibit the skyrmion Hall effect at the angular momentum compensation point. Analysis of the current-induced effective fields reveals that the nonreciprocal transport is due to the asymmetry of the bimeron structure. These findings enhance our understanding of bimerons in ferrimagnets and offer insights for potential applications in spintronic devices.
