A comparison of magnetocaloric effect in Pr0.6A 0.4Mn1-xCrxO3 (A = Ca and Sr; X = 0 and 0.04)

Abstract

In this work, we compare and contrast electrical, magnetic and magnetocaloric properties of undoped (x=0) and 4% Cr-doped Pr 0.6A0.4Mn1-xCrxO3 (A=Ca and Sr). It is shown that while Cr-doping in A=Ca transforms the charge ordered antiferromagnetic insulator into a ferromagnetic metal, it decreases the ferromagnetic transition temperature (TC) and magnetic moment for A=Sr. The change in magnetic entropy, ΔSm=-5.99Jkg K for ΔH=5T around TC=155K of x=0.04 and A=Ca is superior to that of x=0.04 and A=Sr (ΔSm=-2.08Jkg K at TC=290K). The large magnetic entropy in Pr0.6Ca0.4Mn0.96Cr 0.04O3 is attributed to the field-induced suppression of short-range charge-orbital ordering and antiferromagnetic fluctuations present above TC. Our results indicate that Cr substitution in charge ordered manganites is one of the possible ways to enhancemagnetocaloric effect in these complex oxides. © 2010 Elsevier Ltd. All rights reserved.