Abstract
The effects of Ni substitution on structural, magnetic and magnetocaloric properties of Mg0.6Cu0.4-xNixFe2O4 (x=0 and 0.2) ferrites synthesized via sol-gel method has been investigated in this work. XRD patterns confirm the formation of cubic spinel structure with Fd3m space group. Both samples present ferromagnetic (FM)-paramagnetic (PM) phase transitions of second order type with an increment of Curie temperature (T-C) from 630 to 670K for x=0 and 0.2, respectively. The addition of Ni leads to the increase of the values of maximum magnetic entropy change (SMmax) and relative cooling power (RCP) from (1.09Jkg(-1)K(-1) and 136Jkg(-1), for x=0) to (1.38Jkg(-1)K(-1) and 173J.kg(-1), for x=0.2) for an applied magnetic field of H=5T. The magnetic entropy changes for the samples were also estimated by using the mean-field scaling theory, and the results show a difference between the theoretical and experimental values.