The temperature () dependences of magnetization dynamics, especially for magnetic damping anisotropy, have been systematically investigated in well-ordered CoFeAl films with a biaxial anisotropy. It is found that the damping anisotropy factor , defined as the fractional difference of damping between the hard and easy axes, changes from 0.35 to -0.09 as decreases from 300 to 80 K, performing a distinctive reorientation transition at ∼ 200 K. Through the thickness-dependent damping measurement results, the damping anisotropy reorientation is verified to originate from the competitions between the intrinsic anisotropic distribution of bulk spin orbit coupling and the interfacial two-magnon scattering. The former governs the effective damping at high temperatures, while the latter with an opposite fourfold symmetry gradually plays a dominant role at reduced temperatures, leading to the transition of the value from positive to negative. The clear clarification of damping anisotropy variation as well as the underlying mechanism in this study would be of great importance for designing key spintronic devices with optimized dynamic magnetic properties.
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http://dx.doi.org/10.1021/acsami.2c04292 | DOI Listing |
ACS Nano
December 2024
Department of Materials Science and Engineering, National University of Singapore, Singapore117575, Singapore.
A Rashba spin-splitting state with spin-momentum locking enables the charge-spin interconversion known as the Rashba effect, induced by the interplay of inversion symmetry breaking (ISB) and spin-orbit coupling (SOC). Enhancing spin-splitting strength is promising to achieve high spin-orbit torque (SOT) efficiency for low-power-consumption spintronic devices. However, the energy scale of natural ISB at the interface is relatively small, leading to the weak Rashba effect.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
School of Electronic Science and Engineering, Nanjing University, Nanjing, 210023, China.
The prevailing research emphasis has been on reducing the critical switching current density (J) by enhancing the damping-like efficiency (β). However, recent studies have shown that the field-like efficiency (β) can also play a major role in reducing J. In this study, the central inversion asymmetry of Pt-Co is significantly enhanced through interface engineering at the sub-atomic layer of Ta, thereby inducing substantial alterations in the β associated with the interface.
View Article and Find Full Text PDFNano Lett
December 2024
International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, P.R. China.
Half-metals are a class of quantum materials with 100% spin polarization at the Fermi level and have attracted a lot of attention for future spintronic device applications. CrO is one of the most promising half-metal candidates for which the electrical and magnetic properties have been intensively studied in the last several decades. Here, we report the observation of a giant anisotropy (∼1600%) of effective Gilbert damping in the single-crystalline half-metallic (100)-CrO thin films, which is significantly larger than the values observed on conventional ferromagnetic Fe and CoFe thin films.
View Article and Find Full Text PDFMicrosc Res Tech
December 2024
University of Science and Technology of China, Hefei, People's Republic of China.
Atomically resolved scanning tunneling microscope (STM) capable of in situ rotation in a narrow magnet bore has become a long-awaited but challenging technique in the field of strong correlation studies since it can introduce the orientation of the strong magnetic field as a control parameter. This article presents the design and functionality of a piezoelectrically driven rotatable STM (RSTM), operating within a 12 T cryogen-free magnet and achieving a base temperature below 1.8 K, along with spectroscopic capabilities.
View Article and Find Full Text PDFNanomaterials (Basel)
October 2024
Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP), Departamento de Fisica e Astronomia, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal.
The structure and magnetic properties of epitaxial Heusler alloy films (CoFeGe) deposited on MgO (100) substrates were investigated. Films of 60 nm thickness were prepared by magnetron co-sputtering at different substrate temperatures (T), and those deposited at room temperature were later annealed at various temperatures (T). X-ray diffraction confirmed (001) [110] CoFeGe || (001) [100] MgO epitaxial growth.
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