Effect of Zn 2+ -Zr 4+ co-substitution on structural, magnetic and dielectric properties of Ba 0.5 Ca 0.5 Zn x Zr x Fe 12−2x O 19 hexaferrite

In present study, M-type hexaferrite, Ba 0.5 Ca 0.5 Zn x Zr x Fe 12−2x O 19 ( x = 0.00–1.00 with increment of 0.2 per step) were fabricated by the conventional sol-gel technique. The powder X-ray diffraction (PXRD) patterns certified the exchange of Fe 3+ ions by Zn 2+ -Zr 4+ ions. Both the lattice parameters ‘ a ’ and ‘ c ’ have raised from 5.885 ( x = 0.00) to 5.926 Å ( x = 1.0), and from 23.091 (x = 0.00) to 23.455 Å ( x = 1.00), respectively. FESEM micrographs display a slight drop in the size of grains with doping. The maximum saturation magnetization ( M S ≈73.31 emu/g) was detected for x = 0.2 configuration, that is larger than observed value of M S of 72.0 emu/g for pure barium hexaferrite material. The value of coercivity ( H C ) declines significantly from 2151 to 161 Oe with the increase of Zn 2+ -Zr 4+ doping. Mössbauer spectra have been recorded to determine the preferential site occupancy by Zn 2+ -Zr 4+ dopant ions and also the ionic state of Fe-ions. A Mössbauer spectrum shows a doublet and five sextets. All components are in a high spin state as a result of the Fe 3+ ions. The magnetically hard material is converted into a magnetically soft one with the incorporation of Zn 2+ -Zr 4+ dopants. The decreasing trend in M s is also verified by the Mössbauer results. With Zn 2+ -Zr 4+ co-substitution, the average values of hyperfine field ( H f ) decrease from 46.5 ( x = 0.0) to 36.9 T ( x = 1.0), whereas the comparative size of paramagnetic doublet is increased from 0.5 (x = 0.00) to 12.6