Theoretical Investigation of the Magnetocaloric Effect on Stochiometric and Deficient La0.7Ca0.3MnO3 Manganite at Room Temperature

Abstract

In this paper, the magnetic and magnetocaloric properties of La0.7Ca0.3MnO3 (LCMO), La\(_{0.69}\square {~}_{0.01}\)Ca0.3MnO3 (L1) and La0.7Ca\(_{0.29}\square {~}_{0.01}\)MnO3 (L2) systems near a second-order phase transition from a ferromagnetic to a paramagnetic state, have been studied, using a phenomenological model. Based on this model, we are getting the better fits to magnetic transition and we can predict the values of the magnetocaloric effect such as magnetic entropy change, full-width at half-maximum, relative cooling power, and magnetic specific heat change from the calculation of magnetization as a function of temperature under different external magnetic fields. The maximum magnetic entropy change \({(-{\Delta } S}_{M}^{\max }) \)shifts to higher values with one percent of both calcium and lanthanum deficiencies, while the relative cooling power (RCP) and the full-width at half-maximum are reduced. According to the master curve behavior for the temperature dependence of ΔSM predicted for different maximum fields, this work has confirmed that the paramagnetic–ferromagnetic phase transition observed for our sample is of second order.