arXiv subjects

Jintao Shuai

Publications and source records attributed to Jintao Shuai.

3 recordsLinked to original sources

arXiv2026

Magneto-rotation coupling dominates surface acoustic wave driven ferromagnetic resonance in the longitudinal geometry

We present a phonon-magnon extension for the mumax+ micromagnetic framework that implements three surface acoustic wave (SAW) coupling mechanisms: magnetoelastic strain coupling, magneto-rotation coupling arising from the antisymmetric displacement gradient, and spin-rotation (Barnett) coupling from the lattice angular velocity. Six benchmark simulations validate the implementation through SAW-driven domain-wall motion, magnetization switching, magneto-rotation and Barnett field validation, nonreciprocal SAW-magnon absorption from Rayleigh-wave chirality, and spatially resolved coupling in a standing SAW cavity. For the longitudinal geometry (m_0 parallel to k_SAW), we show that the magnetoelastic coupling produces zero transverse torque despite generating a 50 times larger effective field; the magneto-rotation channel provides the sole driving mechanism. The crossover angle below which MR dominates is theta_c approximately 1.1 degrees for YIG parameters. Treating the magneto-rotation coupling constant K_mr as a tunable parameter, we map out the cooperativity phase diagram and show that MR alone can achieve strong coupling (C = 257 for K_mr = 1 MJ/m^3) with an avoided-crossing splitting of 13.6 MHz.

cond-mat.mes-hall↗

arXiv2024

Transport of skyrmions by surface acoustic waves

Magnetic skyrmions in thin films with perpendicular magnetic anisotropy are promising candidates for magnetic memory and logic devices, making the development of ways to transport skyrmions efficiently and precisely of significant interest. Here, we investigate the transport of skyrmions by surface acoustic waves (SAWs) via several modalities using micromagnetic simulations. We show skyrmion pinning sites created by standing SAWs at anti-nodes and skyrmion Hall-like motion without pinning driven by travelling SAWs. We also show how orthogonal SAWs formed by combining a longitudinal travelling SAW and a transverse standing SAW can be used for the 2D positioning of skyrmions. Our results also suggest SAWs offer a viable approach to the transport of multiple skyrmions along multichannel racetrack.

cond-mat.mes-hall↗

arXiv2023

Interaction of surface acoustic waves and magnetic thin films

Surface acoustic waves (SAWs) have emerged as innovative and energy-efficient means to manipulate domain walls (DWs) and skyrmions in thin films with perpendicular magnetic anisotropy (PMA) owing to the magnetoelastic coupling effect. This thesis focuses on the complex interplay between SAWs and magnetic thin films. The effects of the standing SAWs on the magnetisation dynamics in a Ta/Pt/Co/Ir/Ta thin film with PMA were first investigated. SAWs with frequency of 93.35 MHz significantly reduced the coercivity of the thin film by 21% and enhanced the magnetisation reversal speed by 11-fold. Standing SAWs introduce a dynamic energy landscape with a unique spatial distribution, forming striped domain patterns in the thin film. The use of rf signals for generating SAWs inevitably causes a heating effect in the device. This heating effect was examined in situ in a SAW device featuring a Ta/Pt/Co/Ta thin film with PMA using an on-chip platinum thermometer. The temperature increased by 10 K in the presence of SAWs at centre frequency of 48 MHz. The DW velocity was significantly enhanced in the presence of the standing SAWs by a factor of 4 compared to that with temperature change alone owing to the magnetoelastic coupling effect. To understand the SAW-enhanced DW motion, comprehensive micromagnetic simulations were performed on thin films in the presence of travelling SAWs. The findings highlighted that SAW-induced vertical Bloch lines within DWs can simultaneously boost DW depinning and dissipate energy at the DW via spin rotation. The SAW-induced strain gradient can be exploited to control skyrmion motion in a current-free manner. Micromagnetic simulations revealed that the use of orthogonal SAWs, combining horizontal travelling and vertical standing waves, offered a promising approach to direct skyrmion motion along desired trajectories, avoiding undesirable Hall-like motion.

physics.app-ph↗