Landau mean-field analysis and estimation of the spontaneous magnetization from magnetic entropy change in La0.7Sr0.3MnO3 and La0.7Sr0.3Mn0.95Ti0.05O3

In this work, we present the research results of magnetocaloric property and spontaneous magnetization on polycrystalline compounds of La0.7Sr0.3MnO3 and La0.7Sr0.3Mn0.95Ti0.05O3. The magnetic entropy change ΔSM has been determined by two methods: Maxwell relation and Landau theory. The analysis of the ΔSM using the Landau theory are consistent with the experimental ones, indicating the importance of magneto-elastic coupling and electron interaction in the magnetocaloric effect properties of manganite. The critical exponents determined by analyzing the magnetic entropy change are close to the mean-field values. Moreover, the spontaneous magnetization determined using the entropy change is consistent with that deduced from the Arrott curves, confirming that the utilization of the magnetic field dependence of magnetic entropy change to determine the spontaneous magnetization is a valid method.