Composition Dependence of Magnetic and Electrical properties of some Mixed Ferrites

Abstract

Two systems of ferrite samples of the chemical fonnula Lio.5-0.5xNi.Fez.5-o.sx04 ( x= 0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) and Lio.s-o.sxNi.Fez.4-o.sxRo.I04 ( R= Al, Gd, Sm and La & x= 0.0, 0.5 and 1.0) are prepared by the usual ceramic method. x ray diffraction analysis indicated the fonnation of single cubic spinel phase.

In Lio.s-o.s,NixFez.5-o.sx04 system, the lattice parameter increased with increasing Ni content. From IR spectra, it is found that, both ofNi and Li ions occupy B-sites while Fe ions are distributed between A and B sites. The different magnetic properties (magnetization, initial penneability, hysteresis parameters and Curie temperature) were found to decrease with increasing the Ni content while the electrical resistivity increased as Ni content increased. The thermoelectric power measurements showed that the majority of charge carriers are electrons. The magnetic transition from ferrimagnetic state to paramagnetic state is confinned by the magnetic and electrical measurements.

In Lio.s-o.sxNixFez.4-o.sxRo.I04 system, the doping with small amounts of R- ions was found to have great effect on the magnetic and electrical properties. The lattice parameter is found to increase by doping with Gd and Sm, while it decreased by doping withAL In the case of doping with R= La, the lattice parameter did not show any changes relative to the unsubstituted sample. The IR spectra showed that, both the Gd and Sm ions occupy B-sites while Al ions are distributed between A and B-sites and La ions did not enter the spinel