CoFeMnSi (CFMS) and CoFeGaGe (CFGG) Heusler alloys are among the most promising thin film materials for spintronic devices due to a high spin polarization, low magnetic damping and giant/tunneling magnetoresistance ratios. Despite numerous investigations of Heusler alloys magnetic properties performed up to now, magnetoelastic effects in these materials remain not fully understood; due to quite rare studies of correlations between magnetoelastic and other magnetic properties, such as magnetic dissipation or magnetic anisotropy. In this research we have investigated epitaxial CFMS and CFGG Heusler alloys thin films of thickness in the range of 15-50 nm. We have determined the magnetoelastic tensor components and magnetic damping parameters as a function of the magnetic layer thickness. Magnetic damping measurements revealed the existence of non-Gilbert dissipation related contributions, including two-magnon scattering and spin pumping phenomena. Magnetoelastic constant B values and the effective magnetic damping parameter α values were found to be in the range of - 6 to 30 × 10 erg/cm and between 1 and 12 × 10, respectively. The values of saturation magnetostriction λ for CFMS Heusler alloy thin films were also obtained using the strain modulated ferromagnetic resonance technique. The correlation between α and B, depending on magnetic layer thickness was determined based on the performed investigations of the above mentioned magnetic properties.
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http://dx.doi.org/10.1038/s41598-021-87205-y | DOI Listing |
Nat Mater
January 2025
School of Physics and Astronomy, Beijing Normal University, Beijing, China.
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January 2025
Institute of Physics, Johannes Gutenberg University Mainz, 55099, Mainz, Germany.
Spin-Orbit Torque (SOT) Magnetic Random-Access Memory (MRAM) devices offer improved power efficiency, nonvolatility, and performance compared to static RAM, making them ideal, for instance, for cache memory applications. Efficient magnetization switching, long data retention, and high-density integration in SOT MRAM require ferromagnets (FM) with perpendicular magnetic anisotropy (PMA) combined with large torques enhanced by Orbital Hall Effect (OHE). We have engineered a PMA [Co/Ni] FM on selected OHE layers (Ru, Nb, Cr) and investigated the potential of theoretically predicted larger orbital Hall conductivity (OHC) to quantify the torque and switching current in OHE/[Co/Ni] stacks.
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Devol Advanced Automation, Inc., Shenzhen 518101, China.
Direct-drive servo systems are extensively applied in biomimetic robotics and other bionic applications, but their performance is susceptible to uncertainties and disturbances. This paper proposes an adaptive disturbance rejection Zeta-backstepping control scheme with adjustable damping ratios to enhance system robustness and precision. An iron-core permanent magnet linear synchronous motor (PMLSM) was employed as the experimental platform for the development of a dynamic model that incorporates compensation for friction and cogging forces.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, People's Republic of China.
We present a novel resonance mode in capacitive radio frequency (rf) discharges in the presence of an oblique magnetic field at low pressures. We observe the self-excitation of high-frequency harmonics of the current in magnetized capacitive rf discharges through the magnetized plasma series resonance (MPSR) induced by applying a low-frequency power. Utilizing an equivalent circuit model, we reveal that these harmonics arise from the hybrid combination of the magnetic gyration of electrons and the PSR.
View Article and Find Full Text PDFBrain Commun
December 2024
Department of Biomedical Engineering, College of Engineering and Applied Sciences, Columbia University, New York, NY 10027, USA.
Magnetic resonance elastography has emerged over the last two decades as a non-invasive method for quantitatively measuring the mechanical properties of the brain. Since the inception of the technology, brain stiffness has been the primary metric used to describe brain microstructural mechanics. However, more recently, a secondary measure has emerged as both theoretical and experimental significance, which is the ratio of tissue viscosity relative to tissue elasticity.
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