Anisotropic susceptibilities of thin ferromagnetic films within many-body Green's function theory

TL;DR

This paper calculates the static susceptibilities of thin ferromagnetic films with in-plane anisotropy using many-body Green's function theory, highlighting the role of collective excitations and extending previous models to multilayers and higher spins.

Contribution

It generalizes existing Green's function approaches to multilayer ferromagnetic films and spins with S>1/2, emphasizing the significance of collective excitations.

Findings

Collective magnetic excitations are crucial in the paramagnetic regime.

The susceptibilities are successfully calculated within the many-body Green's function framework.

The model extends previous work to multilayer structures and higher spin values.

Abstract

Transverse and parallel static susceptibilities of in-plane uniaxial anisotropic ferromagnetic films are calculated within many-body Green's function theory on the basis of an Heisenberg model. The importance of collective magnetic excitations in particular in the paramagnetic regime are stressed by comparing with mean field calculations. The paper generalizes the work of Jensen et al. [1] to the multilayer case and to spins with S>1/2.