Magnetocaloric properties in La1-xCaxMnO3 thin films: Monte Carlo simulations

The magnelocaloric effect (MCE) of La1-xCaxMnO3 was analyzed when varying the sloichiomelry (x=0.2, 0.33,0.4 and 0.5) and the external applied magnetic held. Simulations were carried out using the Monte Carlo method having a configuration ascribed by the set S-z of all-site spin projections, under the Metropolis algorithm. La1-xCaxMnO3 is characterized for three types of magnetic ions Corresponding to Mn4+ (S=3/2), which are bonded to Ca2+, and Mn3+(e(g)) and Mn3+(e(g), S=2), which are both bonded to La3+. Different interactions must be considered depending On the type of interacting ions. The entropy change Delta S in an isothermal process as well as the temperature change Delta T in an adiabatic process was determined with this model. Both Delta S and Delta T show stoichiometry-dependent maximums near the paramagnetic-ferromagnetic transition temperature (T-c), confirming the order-disorder change at this temperature. The strong dependence in La1-xCaxMnO3 of the MCE on the stoichiometry and the external magnetic field makes this phenomenon important for different technological applications, particularly in refrigeration. (C) 2013 Elsevier B.V. All rights reserved.