Critical Properties and Magnetocaloric Effect in La0.7Ba0.3Mn0.8Ti0.2O3 Ceramic

Abstract

In this work, critical behavior, and magnetocaloric effect, as well as the relationship between these characteristics in polycrystalline sample La0.7Ba0.3Mn0.8Ti0.2O3 has been studied in detail. The positive value of the slope of Arrott plots exhibits that the magnetic phase transition of this sample is of a second order at Curie temperature of 96 K. The critical exponents β, γ, and δ have been determined using various ways including the modified Arrott plots, the Kouvel–Fisher plots, and the critical isotherm analysis. Interestingly, the experimental critical exponent values were β = 0.349 ± 0.002, γ = 1.350 ± 0.033, and δ = 4.868 ± 0.002, which are close to those deduced for the 3D-Heisenberg model below the Curie temperature and for the 3D-XY model above it. Additionally, the ferromagnetic interaction in La0.7Ba0.3Mn0.8Ti0.2O3 was found to be at the borderline of the long-range and short-range magnetic coupling, which was confirmed through the exchange distance decaying of $$ J\left( r \right)\sim r^{ - 4.9} $$. Moreover, the magnetocaloric characteristics of La0.7Ba0.3Mn0.8Ti0.2O3 were consistent with the analysis of critical behavior.