Magnetocaloric effect and critical parameters near the ferromagnetic–paramagnetic phase transition in AMn0.825Ga0.175O3 compound

Abstract

The critical parameters provide important information concerning the interaction mechanisms near the paramagnetic (PM) to ferromagnetic (FM) transition. In this paper, we present a detailed study for the critical behavior of AMn0.825Ga0.175O3 (A = La0.75Ca0.08Sr0.17) sample using the isothermal magnetization data. The critical exponents are estimated by various techniques such as the modified Arrott plot, Kouvel–Fisher plot and critical isotherm. Evaluations of critical exponents yield β = 0.365 ± 0.05, γ = 1.218 ± 0.02 and δ = 4.22 ± 0.02 that are consistent with both predictions for the three-dimensional-Heisenberg model and those reported for materials with the FM transition. The field's dependence on the magnetic entropy change is also analyzed. It shows a power law dependence such as . Finally, the second-order magnetic transition phase is proved by the construction of the universal curve's magnetic entropy change.