Theoretical Work on Magnetocaloric Effect in La0.67Ba0.23Ca0.10Mn0.90Cr0.10O3 Manganite

Abstract

Magnetocaloric properties of the La0.67Ba0.23Ca0.10Mn0.90Cr0.10O3 system near a second-order phase transition from a ferromagnetic (FM) to a paramagnetic (PM) state are investigated. By using a phenomenological model, we can predict the values of the magnetocaloric properties by calculating magnetization as a function of temperature under different external magnetic fields. The magnetic entropy change and the specific heat are obtained. The model parameters were determined and were used to give better fits to magnetic transition. A good agreement is obtained when the numerically predicted results are compared to the experimentally obtained curves. The maximum magnetic entropy change (ΔS M) for La0.67Ba0.23Ca0.10Mn0.90Cr0.10O3 is found to be 578 J/kg K under a magnetic field of 5 T with an RCP value of 193 J/kg for the composition. The (ΔS M) distribution is much more uniform than that of gadolinium (Gd), which is desirable for an Ericson-cycle magnetic refrigerator. These characteristics make manganite a promising candidate for magnetic refrigeration at near room temperature.