Ferrimagnetic zinc ferrite fine powders

Abstract

Partially inverted fine powders of zinc ferrite (ZnFe/sub 2/O/sub 4/) were produced by chemical aerogel synthesis. These powders showed magnetic ordering at temperatures to 250 K. Upon ball milling, a much higher inversion parameter was attained, yielding ferrimagnetic powders having small remanence and coercive fields at room temperature. Due to the small mean particle size, superparamagnetic behavior was seen at temperatures above 25 K. Powder properties were characterized by X-ray diffraction, electron microscopy, calorimetry, magnetometry, and Mossbauer effect spectroscopy techniques.