(Ir-)Reversibility and thermal equilibrium in magnetic domain pattern formation in ultra-thin ferromagnetic films

TL;DR

This paper explores how magnetic domain patterns in ultra-thin ferromagnetic films form and transition between phases, revealing temperature-dependent reversibility and the role of energy barriers influenced by domain size.

Contribution

It provides new insights into the temperature-dependent reversibility of phase transitions and the impact of energy barriers on magnetic domain pattern formation.

Findings

Transitions are reversible at high temperature

Bubble phase is avoided at low temperature

Energy barriers depend on domain size and temperature

Abstract

We investigate the details of pattern formation and transitions between different modulated phases in ultra-thin Fe films on Cu(001). At high temperature, the transitions between the uniform saturated state, the bubble state and the striped state are completely reversible, while at low temperature the bubble phase is avoided. The observed non-equilibrium behavior can be qualitatively explained by considering the intrinsic energy barriers appearing in the system due to the competition between the short-ranged exchange and the long-ranged dipolar interactions. Our experiments suggest that the height of these energy barriers is related to the domain size and is therefore strongly temperature dependent.