Dynamic phase transitions in thin ferromagnetic films

TL;DR

This study uses Monte Carlo simulations to explore how thin ferromagnetic films undergo dynamic phase transitions under oscillatory magnetic fields, revealing distinct behaviors for films with and without surface fields.

Contribution

It provides new insights into the dynamic phase behavior of thin ferromagnetic films, especially regarding the effects of surface fields and the coexistence of phases.

Findings

Dynamic phase transitions depend on field amplitude, frequency, and temperature.

Films with surface fields exhibit separate bulk and surface phase transitions.

A mixed phase state coexists between the two transitions.

Abstract

Monte Carlo simulations have been used to investigate the dynamic phase behavior of a classical Heisenberg spin system with a bilinear exchange anisotropy in a planar thin film geometry. Studies of the field amplitude, frequency and temperature dependence show dynamic phase transitions in films subject to a pulsed oscillatory external field. Thin films with competing surface fields show separate and distinct dynamic phase transitions for the bulk and surface layers of the film. Between the two transitions, a mixed state with coexisting dynamically ordered and dynamically disordered phases is observed in the film. In contrast, the free film with no surface fields shows a single dynamic phase transition as in a bulk system.