Effect of Cu substitution on the structural, magnetic, and dc electrical resistivity response of Co 0.5 Mg 0.5- x Cu x Fe 2 O 4 nanoferrites

Co 0.5 Mg 0.5- x Cu x Fe 2 O 4 ( x = 0.0, 0.2 and 0.4) nanoferrites were prepared by sol–gel auto combustion method. XRD, FT-IR, and HRTEM studies revealed the single-phase spinel cubic crystal structure of all samples with Fd-3 m space group. The lattice constant, calculated using the XRD data, was found in the range 8.3936–8.4735 Å. The average crystallite sizes were found to be in the range of between 38.8 and 49.9 nm. The microstructural behavior and elemental composition of all samples were detected by FE-SEM and EDS, respectively. FTIR curves showed two absorption bands ʋ 1 with higher frequency and ʋ 2 with a lower frequency, indicating metal cation and oxygen bond stretching at tetrahedral and octahedral sites. DC resistivity was decreased with increasing the content of copper. VSM study confirmed the ferrimagnetic behavior of all samples. The values of remnant ratios obtained from VSM data showed their isotropic nature forming single domains ferrimagnetic particles