Crystallographic and magnetic properties of Sr-Ba hexaferrite

Abstract

Synthesis of the Sr-Ba sample was accomplished by the citric sol-gel method. The green sheet of hexagonal Sr0.75Ba0.25Fe12O19, to which the oxide additives were introduced, were prepared by the Dr. Blade method. An x-ray diffractometer, a vibrating sample magnetometer, and a Mossbauer spectrometer were used to examine the influence of oxides additives, such as TiO2, SiO2, Cr2O3, and Al2O3 (0.0 - 10.0 Wt.%) on the crystallographic and the magnetic properties of Sr-Ba hexaferrite. The Mossbauer spectrum of the M-type Sr-Ba ferrite had a superposition of five subspectra associated with the five different sites of the Fe ions, which were in the ferric state. The crystal structure of Sr0.75Ba0.25Fe12O19 is that of a magnetoplumbite of a typical M-type hexagonal ferrite. When the concentration of the additives was increased, the Curie temperature decreased. The addition of 0.25 wt.% of Al2O3 produced the greatest increase in the saturation magnetization of the Sr-Ba hexaferrite compound.