Structural and magnetic characterizations of Ni_xCu_0.8-x Zn_0.2Fe₂O₄ spinel ferrites

Abstract

The Ni-Cu-Zn ferrites are one of the most exciting spinel oxides so far because of its diverse applications. In the current study, the ratio of nickel and copper was varied keeping the concentration of zinc constant primarily aiming to examine its effect on cation distribution as well as structural and magnetic properties. The samples were synthesized via the conventional solid state sintering method at a temperature of 1050 °C then subjected to neutron diffraction studies. The magnetic properties were measured using a vibrating sample magnetometer (VSM) which complements the magnetic measurements from the neutron diffraction experiments. The ferromagnetic behaviors of these Ni-Cu-Zn ferrites were explained using the Y-K model and the canting of the magnetic moments were also measured. The lattice parameter ‘a’ was seen to reduce which results from the replacement of large Cu⁺ ions (0.73${\mathrm{A}}^{°})$ with the smaller ionic radius of ${\mathrm{Ni}}^{+}$(0.69 ${\mathrm{A}}^{\circ }$). To accommodate a large number of cations in the spinel lattice, the oxygen atoms restructure themselves as a result oxygen position parameter increased. The net magnetic moment per unit formula decreases as the Ni content is increased up to a level, after which the net moment increased.

Keywords:

• Neutron diffraction
• spinel ferrite
• cation distribution
• magnetic properties

Acknowlegements

The authors are thankful to Centre for Research Reactor (CRR) of Bangladesh Atomic Energy Commission (BAEC) for their operational support while performing the neutron diffraction experiments.