Preparation of nanocrystalline barium hexaferrite in a glass medium

Barium hexaferrite phase of composition BaO-6Fe<SUB>2</SUB>O<SUB>3</SUB> of dimensions in the range 8.2 to 17.6 nm have been grown within a glass medium by subjecting the latter to a suitable heat treatment. Magnetization measurements on the resultant glass-ceramic have been carried out at temperatures varying from 20 to 300 K. The coercive field H<SUB>c</SUB> is found to be much smaller than that of bulk hexaferrite. The value of H<SUB>c</SUB> increases as the temperature is reduced. Also, H<SUB>c</SUB> shows an increase with the increase of hexaferrite particle size. It appears that the effective anisotropy constant plays an important role in determining this behavior