Relaxation dynamics in a reentrant (FeNi)Mn ferromagnet: A percolation analysis

Abstract
Measurements of the low‐field thermoremanent relaxation in a reentrant (Fe0.65Ni0.35)1−xMnx ferromagnet with x=0.117 reveal a crossover, in the vicinity of the reentrant transition, from equilibrium dynamics in the ferromagnetic phase to age‐dependent, nonequilibrium dynamics in the reentrant phase. Least‐squares fits to two mesoscopically exact relaxation functions show that both dynamic regimes can be described within a common theoretical framework of magnon relaxation on a percolation distribution of fixed, finite domains of dynamically correlated spins.