Tunable Curie Temperature and Magnetocaloric Effect in Mg-Doped (La, Sr)MnO3 Manganites

In this paper, we report on the structural, magnetic, and magnetocaloric properties of La
_0.67
Sr
_0.33-x
Mg
_x
MnO
₃
(x = 0, 0.05, 0.15, and 0.2) manganites synthesized by sol-gel method. The Mg-doping does not modify the crystal structure of the undoped manganite, but results in a slight change of the lattice parameters. Both Curie temperature and saturation magnetization decrease with increasing Mg content. With a field change of 5 T, the maximum values of isothermal entropy change are found to be 2.49, 1.28, 1.37, and 1.30 J/kg· K for x = 0, 0.05, 0.15, and 0.2, respectively. The Mg-doped manganites exhibit a stable magnetocaloric effect in a wide temperature range from ~50 to ~300 K, which is important to magnetic refrigeration.