Magnetocaloric effect and critical parameters near the ferromagnetic-paramagnetic phase transition in AMn(0.825)Ga(0.175)O(3) compound

摘要

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 AMn(0.825)Ga(0.175)O(3) (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 beta = 0.365 +/- 0.05, gamma = 1.218 +/- 0.02 and delta = 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