Spin spirals in ordered and disordered solids

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.

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