Asymmetric Magnetic Relaxation behavior of Domains and Domain Walls Observed Through the FeRh First-Order Metamagnetic Phase Transition

TL;DR

This study investigates the asymmetric magnetic relaxation of domains and domain walls during the first-order metamagnetic phase transition in FeRh, revealing how phase coexistence influences domain wall dynamics and differs from bulk behavior.

Contribution

It provides new insights into the dynamic behavior of domain walls during phase transitions, highlighting the role of phase boundary walls and exchange coupling effects.

Findings

Domain wall relaxation behavior changes with phase coexistence

Domain wall dynamics differ from macroscale magnetic behavior

Phase boundary walls influence magnetic object dynamics

Abstract

The phase coexistence present through a first-order phase transition means there will be finite regions between the two phases where the structure of the system will vary from one phase to the other, known as a phase boundary wall. This region is said to play an important but unknown role in the dynamics of the first-order phase transitions. Here, by using both x-ray photon correlation spectroscopy and magnetometry techniques to measure the temporal isothermal development at various points through the thermally activated first-order metamagnetic phase transition present in the near-equiatomic FeRh alloy, we are able to isolate the dynamic behavior of the domain walls in this system. These investigations reveal that relaxation behavior of the domain walls changes when phase coexistence is introduced into the system and that the domain wall dynamics is different to the macroscale behavior. We attribute this to the effect of the exchange coupling between regions of either magnetic phase changing the dynamic properties of domain walls relative to bulk regions of either phase. We also believe this behavior comes from the influence of the phase boundary wall on other magnetic objects in the system.