The magnetic, magnetic entropy and critical behavior studies in La0.8Ba0.2MnO3 around magnetic phase transition temperature.

Abstract

Magnetocaloric and critical phenomenon investigations were carried out in the crystalline La0.8Ba0.2MnO3 samples prepared through solid state reaction technique. X-ray diffraction (XRD) pattern and its Rietveld refinement using Rietica software confirmed the crystalline phase purity of rhombohedral structure with space group . From magnetic measurements, the Ferromagnetic to paramagnetic (FM-PM) phase transition was observed at TC ~ 285K. The maximum change in magnetic entropy ( ) and relative cooling power (RCP) extracted from magnetic measurements were 3.02 J/kg K and 142.00 J/kg at an applied magnetic field (moH) of 4T. Griffiths phase (GP) with a susceptibility exponent λ = 0.44 was also detected in temperature range of TC < T < TG. Critical exponential analysis indicated the 3D-Ising model like magnetic phase transition at TC. Critical exponent’s reliability was confirmed using models such as universal scaling equations of state and Widom scaling relation. Magnetic entropy change follows the law ΔSM = (moH)n for n = 0.46.