Dynamical Mean Field Theory of Double Perovskite Ferrimagnets

TL;DR

This paper uses dynamical mean field theory to study the magnetic and optical properties of double perovskite ferrimagnets, revealing sensitivities to band structure and discrepancies with experimental transition temperatures.

Contribution

It applies dynamical mean field theory to model ferrimagnetic double perovskites and identifies how band parameters influence magnetic transition temperatures.

Findings

Transition temperatures depend on band structure details.

Calculated transition temperatures are lower than experimental values.

Adjusting band parameters can reconcile theory with experiment.

Abstract

The dynamical mean field method is used to analyze the magnetic transition temperature and optical conductivity of a model for the ferrimagnetic double perovskites such as $Sr_2FeMoO_6$. The calculated transition temperatures and optical conductivities are found to depend sensitively on the band structure. For parameters consistent with local spin density approximation band calculations, the computed transition temperatures are lower than observed, and in particular decrease dramatically as band filling is increased, in contradiction to experiment. Band parameters which would increase the transition temperature are identified.