Magnetocaloric study, critical behavior and spontaneous magnetization estimation in La_0.6Ca_0.3Sr_0.1MnO₃ perovskite

A detailed study of structural, magnetic and magnetocaloric properties of the polycrystalline manganite La_0.6Ca_0.3Sr_0.1MnO₃ is presented. The Rietveld refinement of X-ray diffraction pattern reveals that our sample is indexed in the orthorhombic structure with Pbnm space group. Magnetic measurements display a second order paramagnetic (PM)/ferromagnetic (FM) phase transition at Curie temperature T _c = 304 K. The magnetic entropy change (ΔS _M) is calculated using two different methods: Maxwell relations and Landau theory. An acceptable agreement between both data is noted, indicating the importance of magnetoelastic coupling and electron interaction in magnetocaloric effect (MCE) properties of La_0.6Ca_0.3Sr_0.1MnO₃. The maximum magnetic entropy change (-ΔS ^max _M) and the relative cooling power (RCP) are found to be respectively 5.26 J kg^-1 K^-1 and 262.53 J kg^-1 for μ ₀ H = 5 T, making of this material a promising candidate for magnetic refrigeration application. The magnetic entropy curves are found to follow the universal law, confirming the existence of a second order PM/FM phase transition at T _c which is in excellent agreement with that already deduced from Banerjee criterion. The critical exponents are extracted from the field dependence of the magnetic entropy change. Their values are close to the 3D-Ising class. Scaling laws are obeyed, implying their reliability. The spontaneous magnetization values determined using the magnetic entropy change (ΔS _M vs. M ²) are in good agreement with those obtained from the classical extrapolation of Arrott curves (μ ₀ H/M vs. M ²). The magnetic entropy change can be effectively used in studying the critical behavior and the spontaneous magnetization in manganites system.