Mapping Colossal Magnetoresistance Phase Transitions with the Charge-Carrier Density Collapse Model

TL;DR

This paper models phase transitions in colossal magnetoresistance manganites by integrating phase separation into the charge-carrier density collapse theory, successfully explaining specific heat anomalies and resistivity behavior.

Contribution

It introduces phase separation into the existing theory, providing a comprehensive explanation for thermodynamic and transport properties in Sm0.55Sr0.45MnO3.

Findings

Successfully explains specific heat anomalies in the material.

Accurately models electrical resistivity using scattering mechanisms.

Separates hopping activation energy and bipolaron binding energy contributions.

Abstract

We explain the observed specific heat anomaly (and hence entropy change) in the colossal magnetoresistive manganite Sm0.55Sr0.45MnO3, by introducing phase separation into the current carrier density collapse theory via the notion of the ferromagnetic volume fraction. Within the same framework, we have also been able to explain the observed electrical resistivity of Sm0.55Sr0.45MnO3 by using appropriate expressions governing the scattering mechanisms far away from the transition. Fitting specific heat and resistivity results has allowed us to separate the hopping activation energy of polaronic carriers and the bipolaron binding energy contributions to the exponential behaviour of resistivity in the paramagnetic phase.