Abstract
The series of cobaltite substituted manganese La0.67Pb0.33Mn1-xCoxO3 has been studied and show the effect of cobaltite substitution. The magnetic and magnetocaloric properties of polycrystalline perovskite were investigated. From the measured magnetization data of the samples as a function of magnetic applied field, the associated magnetic entropy change close to their respective Curie temperature T-C and the relative cooling power (RCP) have been determined. The Curie temperature has been analyzed by two methods: a linear extrapolation of m(T) to zero magnetization, and the thermodynamic model. It was found that the maximum change in magnetic entropy for La0.67Pb0.33Mn0.7Co0.3O3 sample reached 3.22 J/kg K at T-C = 260 K for a magnetic field of 10 kOe and RCP=63 J/kg. In view of these results the La0.67Pb0.33Mn1-xCoxO3 compounds are strongly recommended to use as an active magnetic refrigerators. (C) 2010 Published by Elsevier B.V.