Article
Physics, Applied
Haihong Yin, Xiangyu Zheng, Junlin Wang, Yu Zhou, Balati Kuerbanjiang, Guanqi Li, Xianyang Lu, Kaiyu Tong, Yichuan Wang, Jing Wu, Vlado K. Lazarov, Richard F. L. Evans, Roy W. Chantrell, Jianwang Cai, Bo Liu, Hao Meng, Yongbing Xu
Summary: The study reveals that Skyrmions are more likely to form in samples with higher amounts of structural defects, and the density of Skyrmions can be controlled by artificial tuning of the defect amount. By utilizing first-order reversal curves, the stable region and density of Skyrmions can be efficiently controlled in return magnetization loops.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Applied
Zhuoyi Li, Xianyang Lu, Zhe Zhang, Wenjia Li, TaoTao Li, Jian Zhou, Yu Yan, Ruobai Liu, Jun Du, Ronghua Liu, Xinran Wang, Yao Li, Liang He, Jing Wu, Rong Zhang, Yongbing Xu
Summary: This study conducted a comprehensive investigation on improving the spin-orbit torque (SOT) efficiency of the Ta/CoFeB structure by inserting an oxide insulating layer Fe2O3. It was found that a thickness of only 1-5 nm of Fe2O3 significantly reduced the SOT critical switching current by 70% and enhanced the spin Hall angle of Ta. Both types of spin-orbit torques, damping-like and field-like torques, were significantly enhanced. The observed enhanced SOT efficiency was attributed to the atomic diffusion of O from the Fe2O3 underlayer, leading to the partial oxidization of the Ta layer and the Ta/CoFeB interfaces. The results provide a reliable method to improve the SOT performance in perpendicularly magnetized structures for potential real-world applications in spintronic devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Soubhik Kayal, Saikat Maji, Ankan Mukhopadhyay, P. S. Anil Kumar
Summary: In this study, we investigated a heterostructure with perpendicular magnetic anisotropy and broken lateral symmetry. By utilizing the spin-Hall effect and lateral space inversion asymmetry, we enhanced the efficiency of spin-orbit torque and achieved a lower critical current density for current-induced magnetization reversal.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Qixun Guo, Zhongxu Ren, He Bai, Xuemin Wang, Guanghua Yu, Wei He, Jiao Teng, Tao Zhu
Summary: The study experimentally investigated the perpendicular magnetic anisotropy properties of CoFeB/MgO films on 3d light-metal vanadium. It observed a sign change of effective torque fields with the increase of vanadium thickness, indicating a competition of multiple effects on current-induced torques in the weakly spin-orbit coupled V/CoFeB/MgO multilayers. These findings have implications for the fundamental understanding of current-induced torque and further device applications using 3d light transition-metal based heterostructures.
Article
Physics, Applied
B. Ravi Kumar, Sreekar Guddeti, P. S. Anil Kumar
Summary: The magnetic field driven domain-wall motion in out-of-plane magnetized Ta/Pt/CoFeB/Pt multilayers, both as-deposited and annealed, was investigated using Kerr microscopy. The study focused on the modified interfacial Dzyaloshinskii-Moriya interaction (iDMI) that controls the dynamics of chiral domain walls. The strength of iDMI was found to decrease with increasing CoFeB thickness and annealing temperature, which can be attributed to changes in the interface properties and annealing-induced effects.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Physics, Applied
V. Vlaminck, L. Temdie, V. Castel, M. B. Jungfleisch, D. Stoeffler, Y. Henry, M. Bailleul
Summary: We propose a near-field diffraction model for spin waves in perpendicularly magnetized films, which is applicable in any geometries of excitation fields. This model utilizes the Kalinikos-Slavin formalism to express the dynamic susceptibility tensor in k-space and calculates the diffraction patterns via inverse 2D-Fourier transform of the response functions. We demonstrate a high level of quantitative agreement between our model and MuMax3 micro-magnetic simulations on two different antenna geometries. Our method is of great significance for studying spin wave diffraction in perpendicularly magnetized films and can be readily applied in the future designs of magnon beamforming and interferometric devices.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Jinwu Wei, Xiao Wang, Baoshan Cui, Chenyang Guo, Hongjun Xu, Yao Guang, Yuqiang Wang, Xuming Luo, Caihua Wan, Jiafeng Feng, Hongxiang Wei, Gen Yin, Xiufeng Han, Guoqiang Yu
Summary: Synthetic antiferromagnets (SAFs) show potential in next-generation spintronic devices due to zero net magnetization and high thermal stability, despite typically requiring an in-plane effective magnetic field. A new study demonstrates field-free switching in an all-SAF system with significantly reduced net magnetization, showing robustness up to approximately 460 K.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Physics, Applied
Sang Sun Lee, Tae-Seong Ju, Hee-Sung Han, Mi-Young Im, Changsoo Kim, Kyoung-Woong Moon, Seungmo Yang
Summary: In this study, we investigated the effect of atomic-scale interface engineering by inserting a Ta layer between the CoFeB/MgO interface on perpendicular magnetic anisotropy, saturation magnetization, and Dzyaloshinskii-Moriya interaction. Our findings contribute to the development of optimized CoFeB-based skyrmion hosting materials.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Masaaki Tanaka, Motoharu Furuta, Tomoyuki Ichikawa, Masaya Morishita, Yu-Min Hung, Syuta Honda, Teruo Ono, Ko Mibu
Summary: This study demonstrated the generation of perpendicularly spin-polarized electronic currents using a tunnel spin-filtering effect through insulative Fe-rich cobalt ferrite CoxFe3-xO4+delta (I-CFO) barriers with perpendicular magnetic anisotropy (PMA). The combination of well-controlled compositions and lattice strains in spinel-type C-CFO and I-CFO films is applicable as a spin-injection source for spintronics devices when perpendicularly spin-polarized electronic currents are required.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Taehyun Kim, Quynh Anh T. Nguyen, Gyu Won Kim, Min Hyeok Lee, Seok In Yoon, Sonny H. Rhim, Young Keun Kim
Summary: Spin-orbit torque (SOT) based magnetization switching is a current area of interest, and we propose a W-Si alloy as a potential spin current-generating layer in nonvolatile embedded memory and logic devices. Experimental results confirm the required properties of the proposed W-Si/CoFeB heterostructures.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Man Yang, Bingfeng Miao, Jun Cheng, Kang He, Xi Yang, Yulun Zeng, Ziqiang Wang, Liang Sun, Xiangrong Wang, Antonio Azevedo, Subhankar Bedanta, Haifeng Ding
Summary: This study reports spin-charge conversion in perpendicular magnetized Co/Pd multilayers, observing the anomalous inverse spin Hall effect (AISHE) and finding that the sign and magnitude of AISHE can be regulated by the magnetization of the multilayers.
Article
Chemistry, Multidisciplinary
Lizhu Ren, Chenghang Zhou, Xiaohe Song, Herng Tun Seng, Liang Liu, Chaojiang Li, Tieyang Zhao, Zhenyi Zheng, Jun Ding, Yuan Ping Feng, Jingsheng Chen, Kie Leong Teo
Summary: Electrically manipulating magnetic moments by spin-orbit torque (SOT) has potential applications in magnetic memories and logic devices. In this study, highly textured, polycrystalline Heusler alloy MnxPtyGe (MPG) films were found to exhibit reversible switching of magnetization with low switching current density. Additionally, MPG shows a memristive characteristic and the ability for deterministic field-free switching of magnetization.
Article
Physics, Multidisciplinary
Ying Cao, Zhicheng Xie, Zhiyuan Zhao, Yumin Yang, Na Lei, Bingfeng Miao, Dahai Wei
Summary: This paper investigates the performance of spin-orbit torque in heavy metal/ferromagnetic metal periodic multilayers. A series of perpendicular magnetized multilayers were successfully fabricated and the thickness of the Ni layer was varied to study the spin-orbit torque. The efficiency of the spin-orbit torque was found to be effectively modulated by the ratio of Pt and Ni in the multilayers.
Article
Nanoscience & Nanotechnology
Tianli Jin, Gerard Joseph Lim, Han Yin Poh, Shuo Wu, Funan Tan, Wen Siang Lew
Summary: This study proposes a technique to modulate the spin reflection and spin density of states within a heavy-metal Pt through interfacing with a dielectric MgO layer. The researchers demonstrate tunability of the effective out-of-plane spin torque acting on the ferromagnetic Co layer, enabling current-induced SOT magnetization switching without the assistance of an external magnetic field. The influence of the MgO layer thickness on effective SOT efficiency shows saturation at 4 nm, while up to 80% of field-free magnetization switching ratio is achieved with the MgO between 5 and 8 nm. By substituting the dielectric with Ti or Pt, the researchers confirm that the MgO layer is indeed responsible for the observed field-free magnetization switching mechanism.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Lizhu Ren, Liang Liu, Xinyu Shu, Weinan Lin, Ping Yang, Jingsheng Chen, Kie Leong Teo
Summary: The experimental demonstration of current-induced spin-orbit torque (SOT) magnetization switching in a ferrimagnetic D0(22)-Mn3Ge film with high bulk PMA and thermal stability suggests it as a promising candidate for high-density SOT magnetic random-access memory devices. The large effective damping-like SOT efficiency and magnetization switching can be explained by the double-spin source layers and negative-exchange interaction of the ferrimagnet.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Engineering, Electrical & Electronic
E. Raymenants, O. Bultynck, D. Wan, T. Devolder, K. Garello, L. Souriau, A. Thiam, D. Tsvetanova, Y. Canvel, D. E. Nikonov, I. A. Young, M. Heyns, B. Soree, I. Asselberghs, I. Radu, S. Couet, V. D. Nguyen
Summary: In this study, domain wall devices based on perpendicular magnetic tunnel junctions with a hybrid free layer design were developed to achieve electrical read and write, as well as fast domain wall motion driven via spin-orbit torque. The devices showed good performance in terms of tunnelling magnetoresistance readout, spin-transfer torque writing, and domain wall depinning efficiency. Overall, the domain wall conduit based on a synthetic antiferromagnet demonstrated potential for reliable domain wall motion and faster write speed compared to a device based on Pt/Co.
NATURE ELECTRONICS
(2021)
Article
Physics, Multidisciplinary
Mauro Fanciulli, Matteo Pancaldi, Emanuele Pedersoli, Mekha Vimal, David Bresteau, Martin Luttmann, Dario De Angelis, Primoz Rebernik Ribic, Benedikt Roesner, Christian David, Carlo Spezzani, Michele Manfredda, Ricardo Sousa, Ioan-Lucian Prejbeanu, Laurent Vila, Bernard Dieny, Giovanni De Ninno, Flavio Capotondi, Maurizio Sacchi, Thierry Ruchon
Summary: This study reports experimental evidence of magnetic helicoidal dichroism observed in the interaction of an extreme ultraviolet vortex beam with a magnetic vortex. Numerical simulations show that this dichroism is based on the interference of light modes with different orbital angular momenta. This observation provides insights into the interplay between orbital angular momentum and magnetism, and sets the framework for developing new analytical tools for investigating ultrafast magnetization dynamics.
PHYSICAL REVIEW LETTERS
(2022)
Review
Nanoscience & Nanotechnology
Felix Trier, Paul Noel, Joo-Von Kim, Jean-Philippe Attane, Laurent Vila, Manuel Bibes
Summary: Oxide materials exhibit a wide range of functional properties, where electron correlations and spin-orbit coupling play significant roles. Recent advances in oxide spin-orbitronics have led to the realization of exotic phenomena and new functionalities for spintronics applications. The future prospects for this field involve further exploration of spin-charge interconversion, topological spin textures, and the influence of ferroelectricity on spin-orbit-driven effects.
NATURE REVIEWS MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Trevor P. Almeida, Steven Lequeux, Alvaro Palomino, Ricardo C. Sousa, Olivier Fruchart, Ioan-Lucian Prejbeanu, Bernard Dieny, Aurelien Masseboeuf, David Cooper
Summary: This study investigates the magnetism of a NiFe PSA-STT-MRAM nanopillar using off-axis electron holography. The results show that the PSA of the nanopillar is maintained up to at least 250 degrees Celsius, with a moderate decrease in magnetic induction. Therefore, PSA provides significant stability in STT-MRAM applications.
Article
Nanoscience & Nanotechnology
D. Sanchez Hazen, B. M. S. Teixeira, D. Salomoni, S. Auffret, L. Vila, R. C. Sousa, I. L. Prejbeanu, L. D. Buda-Prejbeanu, B. Dieny
Summary: This work experimentally confirms the working principles of a double magnetic tunnel junction (DMTJ) for highly efficient spin-transfer-torque (STT) switching. The use of an assistance layer (ASL) in the DMTJ improves the STT efficiency compared to single MTJ stacks.
Article
Nanoscience & Nanotechnology
P. B. Veiga, A. Mora-Hernandez, M. Dammak, S. Auffret, I. Joumard, L. Vila, Liliana D. Buda-Prejbeanu, I. L. Prejbeanu, B. Dieny, R. C. Sousa
Summary: This study reports on the low temperature characteristics of optimized magnetic tunnel junctions for cryogenic operation. The magnetic and electrical properties of four different structures were characterized, with insertions of Mg, Ru, and permalloy (Py) to reduce the effective anisotropy of the storage layer. A Py insertion layer resulted in higher figures of merit (FOM), with an FOM of 3.78k(B)T(op)/mu A and switching energy E-sw below 655 fJ for devices operating at T-op = 10 K. Additionally, a method to optimize the reference layer stray field was implemented for 20 nm diameter devices using a synthetic antiferromagnetic layer for full compensation.
Article
Nanoscience & Nanotechnology
Titiksha Srivastava, Yanis Sassi, Fernando Ajejas, Aymeric Vecchiola, Igor Ngouagnia Yemeli, Herve Hurdequint, Karim Bouzehouane, Nicolas Reyren, Vincent Cros, Thibaut Devolder, Joo-Von Kim, Gregoire de Loubens
Summary: This study combines magnetic force microscopy, broadband ferromagnetic resonance, and micromagnetics simulations to show that a high-frequency mode accompanies the skyrmion lattice phase in thin-film multilayers of [Pt/FeCoB/AlOx](20). This mode involves the precession of skyrmion cores, generating 50-80 nm wavelength spin waves in the uniformly magnetized background. The observations are made possible by a low Gilbert damping constant, which is almost an order of magnitude lower than in similar ultrathin materials. The simulations also reveal the complex three-dimensional spin structure of the skyrmion cores, which plays a crucial role in spin wave generation.
Article
Materials Science, Multidisciplinary
A. Mouhoub, F. Millo, C. Chappert, J- Kim, J. Letang, A. Solignac, T. Devolder
Summary: We developed a reliable method to quantify the interlayer exchange coupling and intralayer exchange stiffness in synthetic antiferromagnets, and applied it to a specific material platform. We found that the interplay between the two exchange interactions leads to a gradient of magnetization orientation across the stack, which nontrivially affects its hysteresis and spin wave eigenmodes. Using micromagnetic simulations and experimental measurements, we determined the magnetic parameters that best describe the sample behavior, revealing the independence of exchange stiffness on thickness and the variation of interlayer exchange coupling with thickness.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Louis Farcis, Bruno M. S. Teixeira, Philippe Talatchian, David Salomoni, Ursula Ebels, Steiphane Auffret, Bernard Dieny, Frank A. Mizrahi, Julie Grollier, Ricardo C. Sousa, Liliana D. Buda-Prejbeanu
Summary: Spintronic devices have gained attention in unconventional computing due to their non-volatile memory, fast response, and small size. In this study, we demonstrate how voltage driven magnetization dynamics of dual free layer perpendicular magnetic tunnel junctions can mimic spiking neurons in hardware. The device's field-free operation and robustness against external magnetic fields make it suitable for dense neural networks. The low energy consumption (4-16 pJ/spike) and scalability of the device are important advantages for embedded applications. This compact perpendicular magnetic tunnel junction structure could enable sub-100 nm size elements in spiking neural networks.
Article
Multidisciplinary Sciences
Lukas Koerber, Christopher Heins, Tobias Hula, Joo-Von Kim, Sonia Thlang, Helmut Schultheiss, Juergen Fassbender, Katrin Schultheiss
Summary: Magnons are elementary excitations in magnetic materials that can undergo nonlinear multimode scattering processes. By harnessing the interaction between magnon modes, pattern recognition can be achieved. Experimental results show that different azimuthal modes can be excited through three-magnon scattering, with amplitude dependent on the input sequences. Recognition rates as high as 99.4% can be achieved for four-symbol sequences using scattered modes, even in the presence of amplitude noise.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Applied
Y. Peng, G. Malinowski, J. Gorchon, J. Hohlfeld, D. Salomoni, L. D. Buda-Prejbeanu, R. C. Sousa, I. L. Prejbeanu, D. Lacour, S. Mangin, M. Hehn
Summary: Single-shot all-optical helicity-independent switching is achieved in Co/Ho multilayers with varying thicknesses and repetition numbers. Despite larger spin-orbit coupling, which would increase dissipation of angular momentum to the lattice, the pulse duration versus fluence state diagram is similar to the Gd-based system.
PHYSICAL REVIEW APPLIED
(2023)
Article
Physics, Multidisciplinary
K. Mishra, T. G. H. Blank, C. S. Davies, L. Aviles-Felix, D. Salomoni, L. D. Buda-Prejbeanu, R. C. Sousa, I. L. Prejbeanu, B. Koopmans, Th. Rasing, A. V. Kimel, A. Kirilyuk
Summary: Recent works have demonstrated the all-optical switching of magnetization in Tb/Co multilayers using ultrashort laser pulses, while the same process is not achievable in TbCo alloys. In this study, we provide a plausible explanation for this difference based on the angular momenta treatment and gyromagnetic ratio of rare-earth-based ferrimagnets. Furthermore, we investigate the composition-dependent dynamic behavior of the switching process in Tb/Co multilayers through single-shot time-resolved pump-probe experiments, revealing it deviates from the accepted framework applicable to Gd-based systems and Mn-containing Heusler alloys.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
T. Devolder, S-M Ngom, A. Mouhoub, J. Letang, J- Kim, P. Crozat, J-P Adam, A. Solignac, C. Chappert
Summary: We studied how to characterize a population of spin waves by analyzing the electrical microwave noise. The noise contains contributions from both incoherent spin waves and electronic fluctuations. By separating these contributions, we can obtain information about the magnetic susceptibility and the mode-resolved effective magnon temperature.