Critical behaviors near the paramagnetic-ferromagnetic phase transitions of La0.47Eu0.2Pb0.33MnO3 and La0.47Y0.2Pb0.33MnO3 perovskites

Structural and critical behaviors of both La0.47Eu0.2Pb0.33MnO3 (LEPMO) and La0.47Y0.2Pb0.33MnO3 (LYPMO) perovskite samples have been investigated in this work. Rietveld refinements of X-ray diffraction patterns show that samples are single phase and crystallize in the orthorhombic system with Pnma space group with unit cell volume and crystalline domain size higher for LEPMO than LYPMO. Arrott plots show a second-order phase transition for both compounds. The critical properties near ferromagnetic-paramagnetic phase transition have been analyzed from data of static magnetization measurements near TC through various techniques. The estimated critical exponents β, γ and δ for our samples are close to the theoretical prediction from the 3D-Ising model with value of β lower (respectively, γ and δ higher) for LEPMO than LYPMO compound. This can be related to the reduction of the double exchange coupling of Mn3+-O2−-Mn4+ and the reduction of the crystalline domain size when replacing Eu by Y in La0.47Eu0.2Pb0.33MnO3 system.