The effect of Co doping on structural, magnetic and magnetocaloric properties of La0.8Ca0.2Mn1-xCoxO3 perovskites (0 ≤ x ≤ 0.3)

Abstract

Studies of the structural, magnetic and magnetocaloric properties of polycrystalline La 0.8 Ca 0.2 Mn 1-x Co x O 3 compounds (0 ≤ x ≤0.3) perovskite manganites were carried out. Samples were synthesized by sol–gel process and then heated at 1000°C for 3 h. X-ray powder diffraction and magnetic measurements were used to investigate the structural and magnetic properties. Rietveld analysis shows that the samples crystallize in the orthorhombic structure with Pnma space group. Crystallographic analysis shows a variation in lattice parameters as cobalt substitution increases, accompanied by a variation in the interatomic distances and a small increase in MT–O–MT angles (MT = cobalt and manganese). Magnetocaloric studies on La 0.8 Ca 0.2 Mn 1-x Co x O 3 compounds with x = 0 and x = 0.2 have been investigated by measuring the magnetization as a function of temperature. At 2 T, the maximum magnetic entropy [Formula: see text] is about 3.09 J⋅Kg-1⋅K-1 and 1.123 J⋅Kg-1⋅K-1 for x = 0 and 0.2, respectively. Besides, the RCP value decreases with increasing Co content from 55.845 J⋅Kg-1 to 49.971 J⋅Kg-1. Also, the existence of Griffiths Phase and its influence in the phase transition is discussed.