Realistic Estimation of Critical Exponents for Predicting the Magnetocaloric Effect in La0.7Sr0.3–xSmxMn0.95Ni0.05O3 (x = 0, 0.05, 0.10, 0.15) Manganites

Abstract

In this article, is introduce a calculation approach derived from integrating the Landau theory with the Arrott–Noakes equation. Employing a creative formulation, is conduct simulations to explore the magnetic entropy change, $-\mathrm{\Delta }{\mathrm{S}}_{\mathrm{M}}$ within a random ferromagnetic system. This theoretical approach is used for the examination of a given La_0.7Sr_0.3–xSm_xMn_0.95Ni_0.05O₃ (x = 0, 0.05, 0.10, 0.15) manganites. Initially, the critical exponents (𝛾; 𝛽) of these compounds are estimated. It has been noted that the magnetic behavior of the examined materials near the phase transition deviate from the standard patterns observed in typical universality classes. Subsequently, these exponents are exploited to simulate the isothermal $-\mathrm{\Delta }{\mathrm{S}}_{\mathrm{M}}(\mathrm{H},\mathrm{T})$ curves under higher magnetic fields. The predicted relative cooling power values reach 420.3, 415.7, 412.5, and 408.4 J.kg⁻¹K⁻¹ under 10 T applied magnetic field for La_0.7Sr_0.3–xSm_xMn_0.95Ni_0.05O₃ with x = 0, 0.05, 0.10 and 0.15, respectively.