Effect of Cobalt Doping on Magnetocaloric Properties of La 0.8 Na 0.2 Mn 1-x Co x O 3 Manganite

The La 0.8 Na 0.2 Mn 1-x Co x O 3 (0 ≤ x ≤ 0.06) manganite are prepared by the sol gel–based Pechini route. The effect of substitution in Mn site with Co upon the structural, magnetic, and magnetocaloric properties has been analyzed by means X-ray diffraction and linear extracting magnetometer. These nanoparticles crystallize in a rhombohedral symmetry with R3-c space group without any detectable impurity phase. All prepared sample show a paramagnetic (PM) ferromagnetic (FM) phase transition near the critical temperature T c . In fact, the experimental results confirm that Mn site substitution with Co decreases the Curie temperature T c . Magnetocaloric results revealed large relative cooling power RCP values making our samples potential candidate for magnetic refrigeration applications. Referring to the universal data, we revealed a second-order nature of magnetic phase transition for all samples following the mean field approximation.