Effect of Co substitution on magnetocaloric effect in La 0.67Pb 0.33Mn 1− xCo xO 3 (0.15 ≤ x ≤ 0.3)

Abstract

The series of cobaltite substituted manganese La 0.67Pb 0.33Mn 1− x Co x O 3 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 La 0.67Pb 0.33Mn 0.7Co 0.3O 3 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 La 0.67Pb 0.33Mn 1− x Co x O 3 compounds are strongly recommended to use as an active magnetic refrigerators.