Magnetocaloric effect and critical behavior of the La 0.75 Ca 0.1 Na 0.15 MnO 3 compound.

In this paper, we have studied the critical behavior and the magnetocaloric effect (MCE) simulation for the La 0.75 Ca 0.1 Na 0.15 MnO 3 (LCNMO) compound at the second order ferromagnetic-paramagnetic phase transition. The optimized critical exponents, based on the Kouvel-Fisher method, were found to be: β = 0.48 and γ = 1. These obtained values supposed that the Mean Field Model (MFM) is the proper model to analyze adequately the MCE in the LCNMO sample. The isothermal magnetization M ( H , T ) and the magnetic entropy change -Δ S M ( H , T ) curves were successfully simulated using three models, namely the Arrott-Noakes equation (ANE) of state, Landau theory, and MFM. The framework of the MFM allows us to estimate magnetic entropy variation in a wide temperature range within the thermodynamics of the model and without using the usual numerical integration of Maxwell relation.