Magneto- and Baro- Caloric Responses in Magnetovolumic Systems

TL;DR

This paper presents a mean-field thermodynamic model to analyze magneto- and baro-caloric effects in magnetovolumic systems, including phase transitions and exchange interactions, and compares results with experimental data.

Contribution

The study introduces a comprehensive mean-field model incorporating magnetovolumic effects to predict caloric responses in complex magnetic materials.

Findings

Model reproduces experimental caloric trends

Identifies conditions for first-order phase transitions

Explores effects of exchange interaction inversion

Abstract

By means of a mean-field model extended to include magnetovolumic effects we study the effect of external fields on the thermal response characterized either by the isothermal entropy change and/or the adiabatic temperature change. The model includes two different situations induced by the magnetovolumic coupling. (i) A first order para- ferromagnetic phase transition that entails a volume change. (ii) An inversion of the effective exchange interaction that promotes the occurrence of an antiferromagnetic phase at low temperatures. In both cases, we study the magneto- and baro-caloric effects as well as the corresponding cross caloric responses. By comparing the present theoretical results with available experimental data for several materials we conclude that the present thermodynamical model reproduces the general trends associated with the considered caloric and cross caloric responses.