Magnetic properties and magnetocaloric effect in Fe-doped La0.6Ca0.4MnO3 with short-range ferromagnetic order

Abstract

The magnetic properties and magnetocaloric effect of La0.6Ca0.4Mn1-xFexO3 (x = 0–0.04) compounds fabricated by solid-state reaction have been studied. Magnetization measurements versus temperature revealed a decrease of the ferromagnetic-paramagnetic phase transition temperature (TC) with increasing Fe-doping content. The TC values determined for the samples with x = 0, 0.02 and 0.04 are about 260, 254 and 236 K, respectively. Based on magnetic-field dependences of magnetization, M(H), the magnetic entropy change (ΔSm) of the samples were calculated. Under an applied field change ΔH = 30 kOe, the maximum |ΔSmax| value decreases from 5.74 Jkg−1 K−1 for x = 0 to about 2.62 Jkg−1 K−1 for x = 0.04. These values correspond to relative cooling powers 140–180 J/kg, which are comparable to those of other manganites. Analyzing magnetic-field dependences of |ΔSm| for the samples indicates their power-law relation. Based on Banerjee's criteria and Franco's universal curves related to the magnetic-entropy change, we assess magnetic order existing in the samples.