The small polaron crossover transition in colossal magnetoresistance (CMR) manganites

TL;DR

This paper models the small-to-large polaron crossover in CMR manganites, explaining their magnetic and transport properties, including resistivity drops and phase transitions, using a combined double exchange and polaron approach.

Contribution

It introduces a unified formalism combining double exchange and polaron models to describe magnetic and transport phenomena in CMR manganites.

Findings

Reproduces rapid resistivity drop below T_C

Achieves realistic CMR ratios

Models first-order-like magnetic phase transition

Abstract

Based on the combined model of the double exchange and the polaron, we have studied the small-to-large polaron crossover transition and explored its effects on the magnetic and transport properties in colossal magnetoresistance (CMR) manganites. We have used the variational Lang-Firsov canonical transformation, and shown that the magnetic and transport properties of both high and low $T_C$ manganites are well described in terms of a single formalism. We have reproduced the rapid resistivity drop below $T_C$, a realistic CMR ratio, and the {\it first-order-like} sharp magnetic phase transition, which are observed in low $T_C$ manganites.