A novel lowhyphen;temperature preparation of several ferrimagnetic spinels and their magnetic and Mouml;ssbauer characterization

摘要

Ultrafine subdomain particles of NiFe2O4, Ni0.5Zn0.5Fe2O4, and CoFe2O4were prepared under mild hydrothermal conditions by precipitating from metal nitrates. Magnetic and Mouml;ssbauer effect measurements revealed the superparamagnetic nature of these ferrite particles. The crystallite sizes were in the range 5.0ndash;20.0 nm with a very narrow particle size distribution. The magnetic properties and Mouml;ssbauer hyperfine parameters of these subdomain ferrite particles are somewhat different from those reported for multidomain bulk materials. The hydrothermal ferrite powders were found to sinter to almost theoretical density with little or no intergranular porosity.