Thermal effect on microwave pulse driven magnetization switching of Stoner particle

TL;DR

This study investigates how finite temperature affects the efficiency of microwave pulse-driven magnetization switching in nanoparticles, revealing optimal conditions related to particle shape and size for practical applications.

Contribution

It extends the understanding of CCMP-driven magnetization reversal by analyzing temperature effects and identifying parameters for stable operation in realistic conditions.

Findings

Maximal temperature for reversal increases then decreases with particle size.

Easy-plane shape anisotropy reduces required initial frequency.

Parameters remain stable over wide temperature ranges for larger nanoparticles.

Abstract

Recently it has been demonstrated that the cosine chirp microwave pulse (CCMP) is capable of achieving fast and energy-efficient magnetization-reversal of a nanoparticle with zero-Temperature. However, we investigate the finite temperature, $T$ effect on the CCMP-driven magnetization reversal using the framework of the stochastic Landau Lifshitz Gilbert equation. At finite Temperature, we obtain the CCMP-driven fast and energy-efficient reversal and hence estimate the maximal temperature, $T_{max}$ at which the magnetization reversal is valid. $T_{max}$ increases with increasing the nanoparticle cross-sectional area/shape anisotropy up to a certain value, and afterward $T_{max}$ decreases with the further increment of nanoparticle cross-sectional area/shape anisotropy. This is because of demagnetization/shape anisotropy field opposes the magnetocrystalline anisotropy, i.e., reduces the energy barrier which separates the two stable states. For smaller cross-sectional area/shape anisotropy, the controlling parameters of CCMP show decreasing trend with temperature. We also find that with the increment easy-plane shape-anisotropy, the required initial frequency of CCMP significantly reduces. For the larger volume of nanoparticles, the parameters of CCMP remains constant for a wide range of temperature which are desired for the device application. Therefore, The above findings might be useful to realize the CCMP-driven fast and energy-efficient magnetization reversal in realistic conditions.