Abstract
Synthesis of W-type ferrite compounds without atmosphere controlling was investigated focus on the starting materials. W-type ferrite was hard to synthesize without oxygen controlling because W-type ferrite phase exists only at high temperature above 1390 °C at atmospheric pressure due to the existence of Fe2+ and Fe3+ simultaneously. Our new concept is to use M-type ferrite and Spinel ferrite as starting materials because Spinel ferrite contains bivalent and trivalent 3d metal ions. As results, W-type ferrite was simply obtained by calcining in air through the inter-diffusion between M-type ferrite and Spinel ferrite. The anisotropic W-type ferrite compounds were also obtained by aligning the c-axes of the M-type ferrite grains. We concluded that the synthesis using M-type ferrite and Spinel ferrite as starting materials is effective to generate W-type ferrite independent of kinds of bivalent 3d metal ions without oxygen controlling.
