Abstract
Since practically attainable coercivity for ferrites is relatively small in comparison with anisotropy field, many attempts have been made to enhance the coercivity by chemical and powder metallurgical methods. SrO⋅nFe3O3(n=1-6) powders were attempted to be prepare with glycine nitrate process, which is a self-combustion process using metal-nitrate/glycine complex aqueous solution. The crystal structure and magnetic properties of the powders were investigated. The powders prepared in a beaker were mixtures of a-Fe2O3 and Sr(NO3)2, which transform to M-phase with the coercivity of 7kOe after an appropriate heat-treatment. The change in coercivity by heat-treatment can be attributed to grain size of the M-phase. Spray roasting process can afford to produce Mphase directly, which shows σ(18)=56emu/g, HCJ=5.3kOe.
