Effect of cobalt on structural, magnetic and magnetocaloric properties of La0.8Ba0.1Ca0.1Mn1-xCoxO3 (x = 0.00, 0.05 and 0.10) manganites

We have studied the effect of Co substitution on the structural, magnetic and magnetocaloric (MCE) properties of La0.8Ba0.1Ca0.1Mn1-xCoxO3 compounds with x = 0.00, 0.05 and 0.10. All samples were synthesized using polymerization complex sol-gel method. X-ray diffraction (XRD) studies show that all compositions crystallize in the rhombohedral structure with the R3¯c space group. Rietveld analysis indicates that each (Mn, Co)O6 octahedron has a little distortion and that the θ(Mn, Co)O(Mn, Co) bond angles decreases with increasing Co content. The zero field cooled (ZFC) and field cooled (FC) magnetizations reveal that all samples undergo a paramagnetic-ferromagnetic (PM-FM) phase transition and a large deviation is usually observed between ZFC and FC curves which is due to the presence of competing FM and antiferromagnetic (AFM) interactions leading to a glassy behavior. The Curie temperature (TC) is found to decrease from 282 K for x = 0.00-214 K for x = 0.10. Arrot's plots reveal a second order nature of magnetic transition for all samples, which is also confirmed by landau's theory and universal curves.