Theory of the Spin Reorientation Transition of Ultra-Thin Ferromagnetic Films

TL;DR

This paper develops a microscopic Heisenberg spin model to analyze the temperature-dependent spin reorientation transition in ultra-thin ferromagnetic films, emphasizing the role of surface magnetization.

Contribution

It provides analytic expressions for anisotropy and detailed phase diagrams, advancing understanding of surface effects on magnetic transitions.

Findings

Surface magnetization significantly influences the transition

Analytic temperature-dependent anisotropy expressions derived

Phase diagrams mapped in temperature-thickness space

Abstract

The reorientation transition of the magnetization of ferromagnetic films is studied on a microscopic basis within Heisenberg spin models. Analytic expressions for the temperature dependent anisotropy are derived from which it is seen that the reduced magnetization in the film surface at finite temperatures plays a crucial role for this transition. Detailed phase diagrams in the temperature-thickness plane are calculated.