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 Nd 0.67 Ba 0.33 Mn 1− x Fe x O 3 (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 Fe 3+ and Mn 3+ 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 ( | Δ S M m a x | ) and the relative cooling power (RCP) are respectively 3.91 and 2.97 J Kg −1 K −1 and 265 and 242 J 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, Δ S M ( H ) = a ( μ 0 H ) n , with n =0.59 and 0.64 respectively for x =0 and 0.02 samples at their respective transition temperatures. [ABSTRACT FROM AUTHOR]