Cation distribution, magnetic and hyperfine interaction studies of Ni-Zn spinel ferrites: role of Jahn Teller ion (Cu2+) substitution

This study reports cation distribution, magnetic, and hyperfine interaction studies of Cu2+-substituted mixed Ni-Zn nano-spinel ferrites prepared by combustion technique. X-ray diffraction and electron microscopy were used to study the structural and morphological aspects of all the samples. Rietveld refined diffraction patterns exhibited a cubic-spinel lattice structure with the Fd3m space group for all the samples. Morphological investigations revealed the spherical morphology of particles with some agglomeration. The magnetic properties investigated at 300 K and 5 K implied a soft ferromagnetic character of all the samples. The magnetization at 5 K progressively enhanced due to surface effects. Field-cooled and zero-field-cooled measurements indicated net irreversibility for all the samples. Hyperfine interaction studies revealed the ferrimagnetic nature of Cu2+-substituted mixed Ni-Zn spinel nano-ferrites. All the obtained results show that the prepared nanoparticles are useful for magnetic fluid hyperthermia and other bio-applications.