Magnetic entropy change in perovskite manganites La_(0.7)A_(0.3)MnO_3 La_(0.7)A_(0.3)Mn_(0.9)Cr_(0.1)O_3 (A = Sr, Ba, Pb) and Banerjee criteria on phase transition

摘要

The La_(0.7)A_(0.3)MnO_3, La_(0.7)A_(0.3)Mn_(0.9)Cr_(0.1)O_3 (A = Sr, Ba, Pb) polycrystalline perovskite manganites sample was prepared by the sol-gel technique. The replacement of partial Mn~(3+)/Mn~(4+) by Cr~(3+) (Cr~(3+) with the same electronic configuration as Mn~(4+)) cause the variety of magnetocaloric property and magnetic entropy change. The maximum magnetic entropy change ΔS_h = -1.16 J/kg K and the Relative Cooling Power (about 43.3 J/kg) were obtained from La_(0.7)Sr_(0.3)Mn_(0.9)Cr_(0.1)O_3 in the Cr~(3+) doped series under 1 T magnetic field variation. On this paper, Banerjee criteria had been remarked to distinguish the first-order or second-order phase transition on phase transition of the doped perovskite manganites.