Continuum Double Exchange Model

TL;DR

This paper introduces a continuum model for doped manganites featuring two fermion species interacting with classical spins, revealing a complex zero-temperature phase diagram with multiple stable magnetic and conducting phases.

Contribution

It develops a novel continuum model for doped manganites that captures diverse magnetic and conducting phases at zero temperature, including phase separation.

Findings

Multiple stable phases identified: antiferromagnetic insulator, canted and ferromagnetic conductors.

Rich phase diagram with regions of phase separation.

All phases are stable against phase separation.

Abstract

We present a continuum model for doped manganites which consist of two species of quantum spin 1/2 fermions interacting with classical spin fields. The phase structure at zero temperature turns out to be considerably rich: antiferromagnetic insulator, antiferromagnetic two band conducting, canted two band conducting, canted one band conducting and ferromagnetic one band conducting phases are identified, all of them being stable against phase separation. There are also regions in the phase diagram where phase separation occurs.