Stripes in thin ferromagnetic films with out-of-plane anisotropy

TL;DR

This paper analyzes the zero-temperature phase diagram of thin ferromagnetic films with out-of-plane anisotropy, revealing various magnetic phases, their stability, and the influence of edges, with implications for experimental observations.

Contribution

It provides a universal phase diagram near the reorientation transition, identifying phase boundaries, metastability, and edge effects in thin ferromagnetic films.

Findings

Identification of uniform, canted, SDW, and stripe phases.

Existence of a critical point where SDW and stripes merge.

Hysteresis effects due to phase coexistence.

Abstract

We examine the T=0 phase diagram of a thin ferromagnetic film with a strong out-of-plane anisotropy in the vicinity of the reorientation phase transition (with Co on Pt as an example). The phase diagram in the anisotropy-applied field plane is universal in the limit where the film thickness is the shortest length scale. It contains uniform fully magnetized and canted phases, as well as periodically nonuniform states: a weakly modulated spin-density wave and strongly modulated stripes. We determine the boundaries of metastability of these phases and point out the existence of a critical point at which the difference between the SDW and stripes vanishes. Out-of-plane magnetization curves exhibit a variety of hysteresis loops caused by the coexistence of one or more phases. Additionally, we study the effect of a system edge on the orientation of stripes. We compare our results with recent experiments.