EFFECT OF DOPED SILICON ON STRUCTURE AND MAGNETIC-PROPERTIES OF GAMMA-FE2O3 PARTICLES

The structure of Si-doped gamma-Fe2O3 small particles prepared by dopi ng with different silicon contents has been investigated by X-ray diff raction based on Furuhashi method. The results show that the lattice p arameters decrease gradually with increasing silicon content, indicati ng the formation of a solid solution for Si-doped gamma-Fe2O3. The Si4 + cation in spinel-like structures shows a strong tendency for distrib ution in the tetrahedral site, which to some extent affects the oxygen parameter as well as the mean sizes of tetrahedral and octahedral int erstices. Additionally the formula of Stokes and Wilson was used to ca lculate the effect of doped silicon on grain sizes and lattice distort ions of the samples. It is found that, with increasing silicon content , the grain size decreases significantly while the lattice distortion shows only a little change. Finally, the coercivity and saturation mag netization for Si-doped gamma-Fe2O3 particles are discussed in detail. (C) 1997 Elsevier Science S.A.