An ac-susceptibility study of magnetic relaxation phenomena in the antiskyrmion hosting tetragonal Mn-Pt(Pd)-Sn system

TL;DR

This study investigates the magnetic relaxation dynamics in the antiskyrmion-hosting Mn-Pt(Pd)-Sn system using ac susceptibility, revealing fast relaxation times, phase-dependent behavior, and Arrhenius-law temperature dependence, advancing understanding of antiskyrmion dynamics.

Contribution

It provides the first detailed analysis of ac-magnetic susceptibility and relaxation phenomena in a tetragonal Mn-Pt(Pd)-Sn antiskyrmion host, highlighting phase-dependent relaxation times and high-frequency dynamics.

Findings

Debye-type relaxation with negligible distribution in relaxation times.

Non-monotonic relaxation time variation with phase boundaries.

Relaxation times follow Arrhenius law with energy barriers.

Abstract

Here, we report an exhaustive study of the frequency-dependent ac-magnetic susceptibility of the $D_{2d}$ symmetric Heusler system Mn-Pt(Pd)-Sn that hosts antiskyrmions over a wide temperature range. Magnetic relaxation studies using Cole-Cole formalism reveal a Debye-type relaxation with a nearly negligible distribution in relaxation times. In contrast to the archetypical skyrmion hosts, the high Curie temperature ($ T_C $) of the present system ensures shorter switching times, and, correspondingly, higher frequencies are required to probe the relaxation dynamics. We find a non-monotonic variation in the characteristic relaxation time with distinct maxima at the phase boundaries \textit{via} helical $\longrightarrow$ antiskyrmion $\longrightarrow$ field-polarized states, indicating slower magnetization dynamics over the region of phase coexistence. The temperature-dependent relaxation time across different phases is of the order of $ 10^{-5} - 10^{-4} $ s and follows the well-known Arrhenius law with reasonable values of the energy barriers. The present study concerning the magnetization dynamics in the antiskyrmion host tetragonal Heusler system is an important contribution towards the basic understanding of the dynamical aspects of antiskyrmions for their potential applications.