Doping assisted structural transition in copper substituted MgFe2O4 ferrite: Thermal, electrical and magnetic properties

Abstract

A cubic to tetragonal structure transition has evolved by substitution of Cu2+ ions in magnesium ferrite, fabricated via the sol-gel method. TEM studies revealed quasi-spherical particles for MgFe2O4 and rod-shaped particles for CuFe2O4, suggesting an enhancement of morphological anisotropy with Cu doping. Thermal analysis shows the formation of MgFe2O4 and CuFe2O4 at ~380 oC and ~340 oC respectively, indicating reduction in temperature for the formation of the samples with copper doping. XRD show the structural transition of cubic to tetragonal structure with increasing copper concentration. The dc electrical resistivity decreases with copper doping in MgFe2O4, attributing to the increase in conductivity due to Cu2+-Cu+ ions hopping. MgFe2O4 has been found to have a saturation magnetization of ~23 emu/g and coercive field of ~54 Oe. The saturation magnetization increases while coercivity initially decreased and then increases with increasing copper concentration.