Structural, magnetic, magnetocaloric and critical exponents of oxide manganite La_(0.7)Sr_(0.3)Mn_(0.95)Fe_(0.05)O_3

摘要

In this scientific paper, structural, magnetic, magnetocaloric and critical exponent's properties of La_(0.7)Sr_(0.3)Mn_(0.95)Fe_(0.05)O_3 compound are briefly reviewed. The sample was synthesized by solid state reaction. X-ray powder diffraction analysis at room temperature showed that our sample is single phase without detection of any impurities. The refinement by the Rietveld method indicate that this compound crystallize in the orthorhombic structure with the space group Pnma. The variation of the magnetization versus temperature found that our perovskite has a single transition from the paramagnetic state (PM) to the ferromagnetic state (FM) with increasing temperature and the obtained Curie temperature is T_C = 311 K. The obtained value of | ΔS_M~(MAX)| is about 2.3Jkg~(-1) K~(-1) under an applied magnetic field of 5 T. The achieved results show that our compound is a promising candidate for magnetic refrigeration. Also, to discover the nature of the paramagnetic-ferromagnetic phase transition, for the La_(0.7)Sr_(0.3)Mn_(0.95)Fe_(0.05)O_3 we made an experimental study on the critical behaviour around the FM-PM transition. The value of the Curie temperature and the critical exponent's β, γ and δ were determined using modified Arrott plots (MAP).