Effect of Fe-doping on structural, magnetic and magnetocaloric properties of Nd0.67Ba0.33Mn1-xFexO3 manganites

We have investigated the effect of Fe doping on structural, magnetic and magnetocaloric properties of Nd0.67Ba0.33Mn1-xFexO3 (0 <= x <= 0.1) manganites prepared by solid state reaction method at 1673 K. XRD analysis shows that doping Mn by Fe do not affect the crystal structure of samples due to the same ionic radii of Fe3+ and Mn3+ and hence do not influence physical properties of samples. Magnetization measurements show a ferromagnetic behavior for x=0 and 0.02 samples, whereas compounds with x >= 0.05 present a magnetic glass state (cluster or spin glass). The magnetic entropy change was also studied through the examination of measured magnetic isotherms M(H, T) near T-C. The maximum magnetic entropy change (vertical bar Delta S-M(max)vertical bar) and the relative cooling power (RCP) are respectively 3.91 and 2.97 J Kg(-1) K-1 and 265 and 2423 Kg(-1) at a field change of 5 T, for x=0 and 0.02 samples. These values are compared favorably with those of some others reported manganites, making our samples promising candidates for the magnetic refrigeration. The field dependence of the magnetic entropy change analysis shows a power law dependence, Delta S-M(H)=alpha(mu H-0)(n), with n=0.59 and 0.64 respectively for x=0 and 0.02 samples at their respective transition temperatures. (C) 2014 The Authors. Published by Elsevier Ltd.