Small Magnetic Polaron Picture of Colossal Magnetoresistance in Manganites

TL;DR

This paper proposes a magnetic polaron model to explain colossal magnetoresistance in manganites, highlighting the roles of double exchange, finite bandwidth, and band-like polaron motion in the metal-insulator and magnetic transitions.

Contribution

It introduces a magnetic polaron framework that unifies high-temperature activated transport and low-temperature band-like conduction in manganites.

Findings

Both double exchange and finite bandwidth are crucial for understanding CMR.

Magnetic transition is explained by band-like polaron motion.

The model accounts for the coincidence of metal-insulator and ferromagnetic transitions.

Abstract

We present a small-but-sizeable magnetic polaron picture where transport at high temperatures is activated while at low temperatures it is band-like. We show that both double exchange and finite bandwidth effects are important to understand colossal magnetoresistance as well as the coincidence of the metal-insulator and the ferromagnetic transitions in manganites. The magnetic transition is explained using band-like motion of the polarons.