Landau mean-field analysis of magnetic entropy change and spontaneous magnetization estimation in Nd0.6Sr0.3K0.1MnO3 perovskite

The Nd0.6Sr0.3K0.1MnO3 polycrystalline manganite is synthesized by using the sol–gel procedure. Structural, magnetic and magnetocaloric properties have been systematically investigated. The Rietveld refinement analysis indicates that studied compound is indexed in the orthorhombic system with Pnma space group. Magnetization data display a second-order magnetic phase transition from paramagnetic to ferromagnetic state at Curie temperature. The analysis of the magnetic entropy change is performed by using different methods: classical Maxwell equations and Landau mean-field model. Satisfactory accordance between both data is noticed. The maximum of the magnetic entropy change and the relative cooling power are found to reach 3.06 J.kg−1.K−1 and 180 J.kg−1, respectively, under an external magnetic field of 5 T, making this material considered as potential candidate for room temperature magnetic refrigeration application. The critical exponents are deduced from the field dependence of the magnetic entropy change using a universal power law. The obtained values go in tandem with those related to the 3D-Ising model. According to the mean-field theory, the magnetic entropy change is invested to determine the spontaneous magnetization values. Results match reasonably well with those extracted from the classical extrapolation of Arrott plots.