Structural, dc electrical resistivity and magnetic investigation of Mg, Ni, and Zn substituted Co-Cu nano spinel ferrites

The sol-gel auto-combustion procedure was used to synthesize M (M = Mg, Ni, and Zn) substituted Co0.5Cu0.2M0.3Fe2O4 micro ferrites. X-ray diffraction measurements validated the mono-phase formation and nanocrystalline character of the produced samples. It possesses a monophasic cubic-spinel lattice structure with an average crystallite size ranging from 29.01 to 47.17 nm. The lattice constant determined by XRD analysis falls between 8.374 and 8.474 angstrom. The morphological characteristics were shown using FESEM analysis, which revealed the almost spherical form of grains with sizes ranging from 40, 50, and 74 nm. The compositional verification was undertaken with the help of the EDS analysis which ensured the presence of elements in desired proportions. IR spectra confirm their spinel spectra with the help of the two absorption bands lying between 1200 and 400 cm-1 resembling their two sites: tetrahedral and octahedral. The magnetic saturation (MS), magnetic moment (M)R, and coercivity (Hc) are found to be the highest for the Ni substituted Co-Cu ferrite system, i.e., MS = 49.5 emu/g. The ratio MR/MS for all ferrites is less than 0.5 indicating their ferromagnetic isotropic nature thereby acting as magnetic semiconductors. The electrical properties were measured using the 'two probe technique' with varying temperatures which indicates their semiconducting nature. Ni substituted Co-Cu nanoferrite is preferable for electromagnets and recording purposes the magnetic and electrical behavior of Ni substituted Co-Cu nanoferrite shows its relevance for recording and electromagnetic applications.