Spin spirals in ordered and disordered solids

TL;DR

This paper presents a computational scheme combining KKR and CPA methods to analyze spin spiral magnetic structures and their stability in both ordered and disordered solids, with applications to various alloys and elemental systems.

Contribution

It introduces a novel approach integrating KKR Green's function formalism with CPA to study magnetic structures in disordered materials.

Findings

Calculated spin stiffness for Fe$_x$Ni$_{1-x}$ matches experimental data.

Determined magnetic susceptibility for Cr, Ni, and alloy systems.

Analyzed stability of paramagnetic states in selected materials.

Abstract

A scheme to calculate the electronic structure of systems having a spiral magnetic structure is presented. The approach is based on the KKR (Korringa-Kohn-Rostoker) Green's function formalism which allows in combination with CPA (Coherent Potential Approximation) alloy theory to deal with chemically disordered materials. It is applied to the magnetic random alloys Fe$_x$Ni$_{1-x}$, Fe$_x$Co$_{1-x}$ and Fe$_x$Mn$_{1-x}$. For these systems the stability of their magnetic structure was analyzed. For Fe$_x$Ni$_{1-x}$ the spin stiffness for was determined as a function of concentration that was found in satisfying agreement with experiment. Performing spin spiral calculations the longitudinal momentum-dependent magnetic susceptibility was calculated for pure elemental systems (Cr, Ni) being in non-magnetic state as well as for random alloys (Ag$_x$Pt$_{1-x}$). The obtained susceptibility was used to analyze the stability of the paramagnetic state of these systems.