Modeling of the magnetobarocaloric effect in the framework of the mean-field theory

The magnetobarocaloric effect (MBCE) is studied, which consists in the change of entropy and temperature in a layer of magnetostrictive material upon simultaneous application of a magnetic field and pressure. The MBCE is described in the framework of the generalized mean-field model accounting both the nonlinear dependence of the effective magnetic intensity on magnetization and its dependence on pressure. To test the developed MBCE model, a comparison with experimental data for La0.85Ag0.15MnO3 manganite ceramics is performed. Using a single set of model parameters, the results can be reproduced with good accuracy. Based on the obtained values for the material constants, the thermodynamic efficiency of the Brayton cycle on the magnetobarocaloric effect is calculated. The combined use of magnetic field and pressure allows to significantly increase the efficiency of this cycle (by 10%-20%), while the entropy can increase by 45%.