Thermodynamic modeling of phase separation in manganites

TL;DR

This paper develops a thermodynamic model for phase separation in manganites, capturing static and dynamic behaviors, and is validated through calorimetric measurements and phase diagram analysis.

Contribution

It introduces a phenomenological thermodynamic model that accounts for both static and dynamic phase separation properties in manganites, including out-of-equilibrium features.

Findings

Identification of blocked and unblocked regimes in phase separated manganites

Calorimetric evaluation of free energies of coexisting phases

Construction of a phase diagram illustrating static and dynamic properties

Abstract

We present a phenomenological model based on the thermodynamics of the phase separated state of manganites, accounting for its static and dynamic properties. Through calorimetric measurements on La$_{0.225}$Pr$_{0.40}$Ca$ _{0.375}$MnO$_{3}$ the low temperature free energies of the coexisting ferromagnetic and charge ordered phases are evaluated. The phase separated state is modeled by free energy densities uniformly spread over the sample volume. The calculations contemplate the out of equilibrium features of the coexisting phase regime, to allow a comparison between magnetic measurements and the predictions of the model. A phase diagram including the static and dynamic properties of the system is constructed, showing the existence of blocked and unblocked regimes which are characteristics of the phase separated state in manganites.