Paramagnetic-ferromagnetic transition in a double-exchange model

TL;DR

This paper develops a theoretical framework using Dynamical Mean Field Approximation to analyze the paramagnetic to ferromagnetic transition in a double-exchange model, providing explicit formulas for transition temperature based on electron properties.

Contribution

It introduces a generalized DMFA approach for the double-exchange model and derives an explicit formula for the transition temperature applicable to various electron dispersions.

Findings

Derived explicit formula for transition temperature T_c.

Calculated T_c for semi-circular electron density of states.

Provided a versatile method for analyzing magnetic transitions in double-exchange systems.

Abstract

We study paramagnetic - ferromagnetic transition due to exchange interaction between classical localized magnetic moments and conduction electrons. We formulate the Dynamical Mean Field Approximation equations for arbitrary electron dispersion law, concentration and relation between exchange coupling and the electron band width. Solving these equations we find explicit formula for the transition temperature $T_c$. We present the results of calculations of the $T_c$ for the semi-circular electron density of states.