Preparation of small particles of SrFe12O19with high coercivity by hydrolysis of metal-organic complexes

Small particles (50-60nm) of Sr ferrite (SrFe
12
O
19
) have been synthesized by the hydrolysis method of metal-organic complexes such as metal acetylacetonates or metal ethoxides and subsequent heat-treatments of the precipitates, and their magnetic properties have been studied. X-ray, Mössbauer and electron-microscope studies have been conducted to examine the mechanism of the formation. A coercive force of 6700 Oe, one of the highest values reported so far for isotropic SrFe
12
O
19
samples and close to the theoretical limit, has been obtained. Some of their magnetic properties have been discussed in terms of magnetism of small particles.