Magnetic phase diagram of doped CMR manganites

TL;DR

This paper presents a detailed quantum mechanical analysis of the magnetic phase diagram in doped CMR manganites, highlighting the roles of double-exchange and superexchange interactions in determining magnetic phases.

Contribution

It provides a comprehensive finite temperature phase diagram based on a Hamiltonian including DE and AF interactions, clarifying magnetic structures in CMR manganites.

Findings

The phase diagram matches observed features in CMR manganites.

CE-type AF structure is not stable at x=0.5 in this model.

The formalism accurately describes magnetic phases at finite temperatures.

Abstract

The magnetic phase diagram of the colossal magnetoresistance (CMR) manganites is determined based on the Hamiltonian incorporating the double-exchange (DE) interaction between degenerate Mn $e_g$ orbitals and the antiferromagnetic (AF) superexchange interaction between Mn $t_{2g}$ spins. We have employed the rigorous quantum mechanical formalism and obtained the finite temperature phase diagram which describes well the commonly observed features in CMR manganites. We have also shown that the CE-type AF structure cannot be stabilized at $x$=0.5 in this model.