Explaining the temperature effects on the magnetization dynamics of non-interacting antiferromagnetic nanoparticles across wide ranges of frequencies and damping

Abstract

Owing to their ultrafast spin dynamics, antiferromagnetic nanoparticles based materials are very promising for electronic memory devices that require a specific control of interaction between the spin current and local magnetization of the sublattice. Hence, the elucidation of the dynamics of the magnetization of antiferromagnetic nanoparticles is an essential. In this work, we report an exploration of the dynamics of the magnetization of antiferromagnetic nanoparticles using Fokker–Planck equation susceptive to describe the behavior of the distribution function of the magnetization of non-interacting nanoparticles. The dynamic equation is treated within the framework of matrix continued fractions approach using numerical method for which the magnetization correlation function as well as the complex susceptibility are assessed for different values of temperature across wide ranges of frequencies and damping. The analysis performed within these circumstances reveal that the application of strong magnetic field at any arbitrary angle to the easy axis of the nanoparticle trains a substantial modification of the magnetization dynamics of the corresponding nanoparticle. Moreover, using the simple asymptotic formulae, the obtained results relative to the estimation of the greatest relaxation time reveal a decent agreement with the relaxation time calculated from the infinite hierarchy of linear differential-recurrence equations for the statistical moments. We show that the great sensitivity of the magnetization dynamics to the thermal agitation provides unique information regarding the coupling between the precession of the magnetization and its thermally activated reversal over the saddle point, resulting from influence of the dc field orientation and strength as well as the damping.