Magnetic properties of spindle-type iron fine particles obtained from hematite

Spindle-type iron fine particles have been prepared by reduction of silica- coated-hematite particles. Hydrogen reduction of the coated-hematite cores yielded uniform spindle-type iron particles, which were stabilized by surfa ce oxidation. Narrow particle distributions are observed from TEM measureme nts. X-ray, Mossbauer and magnetization data are in agreement with the pres ence of nanosized alpha -Fe particles, having surface layer of spinel struc ture oxide. Mossbauer spectra show that the oxide surface is superparamagne tic at room temperature. (C) 2001 Elsevier Science B.V. All rights reserved .