Magnetic and Magnetocaloric Properties of Perovskite Pr_0.5Sr_0.5-xBa_xMnO₃

Abstract

This paper studies the effects of A-site substitution by barium on the magnetic and magnetocaloric properties of Pr 0.5 Sr 0.5-x Ba x MnO₃ (x = 0, 0.04, 0.08 and 0.1). The tetragonal crystal structures of the samples are confirmed by room temperature X-ray diffraction. The dependence of the Curie temperature (T C ) and the magnetic entropy change (ΔS M ) on the Ba doping content has been investigated. The samples of all doping contents undergo the second order phase transition. As the concentration of Ba increased, the maximum entropy change (|ΔS M | max ) increased gradually, from 1.15 J kg ?1 K ?1 (x = 0) to 1.36 J kg ?1 K ?1 (x = 0.1), in a magnetic field change of 1.5 T. The measured value of T C is 265 K, 275 K, 260 K and 250 K for x = 0, 0.04, 0.08 and 0.1, respectively. If combining these samples for magnetic refrigeration, the temperature range of ~220 K and 290 K, where |ΔS M |max is stable at ~1.27 J kg ?1 K ?1 and RCP = 88.9 Jㆍg ?1 for ΔH = 1.5 T. Pr 0.5 Sr 0.5-x BaxMnO₃ compounds, are expected to be suitable for magnetic-refrigeration application due to these magnetic properties.