Magnetocaloric Effect and Critical Behavior Around the Phase Transition Temperature in La0.6Sr0.3Ca0.1Mn0.975Fe0.025O3 Manganite

Abstract

We have investigated the structural, magnetocaloric effect along with magnetic phase transition and critical exponent in mixed manganite La0.6Sr0.3Ca0.1 Mn0.975Fe0.025O3(LSCMFe0.025). The structural study using Rietveld refinement of X-ray diffraction pattern indicates a rhombohedral structure with $R\bar {{3}}c$ space group. In fact, magnetic measurements revealed that the sample exhibits the secondorder paramagnetic–ferromagnetic transition. The maximum value of the magnetic entropy change at 5 T applied change in the magnetic field, is 2.18 J kg −1 K −1 for La0.6Sr0.3Ca0.1Mn0.975Fe0.025O3 manganite with T c value of 312 K. The corresponding relative cooling power (RCP) reaches 218.4 J kg −1. The relatively high RCP makes the present compound a promising candidate for magnetic refrigerant. The critical properties of the sample around the paramagnetic–ferromagnetic phase transition were determined through various techniques such as modified Arrott plot (MAP), Kouvel–Fisher (KF) method and critical isotherm (CI) analysis based on the data of static magnetic measurements recorded around the Curie temperature T C. The experimental results have revealed that the sample which exhibits the critical exponents of β = 0.362 ± 0.006, γ = 1.312 ± 0.018, and δ = 4.698 ± 0.002 are close to those expected for the 3D Heisenberg model for LSCMFe0.025 This model was also confirmed by using the field dependence of magnetic entropy change method.