This study was to determine the effects of grain size on the switching properties of lithium ferrite and to establish the best grain size for a fast switching speed, with a minimum increase of coercive force. Lithium ferrite (Li0.5Fe2.5O4) powder prepared by four preparation techniques; flame spraying, commercial techniques, fluid-bed reaction, and Li2CO3+Fe2O3 mixture, was densified by hot pressing or conventional sintering. There was a variation in the grain growth and densification characteristics of the powders, but the magnetic properties were similar for a given grain size. The magnetic properties which were evaluated as a function of grain size were squareness, switching coefficient, coercive force, and switching time. These properties were evaluated for a 0.7 to 15.0 μ grain-size range in order to establish the effects of grain size on switching speed and coercive force. It is shown that samples with a reduced grain size have twice the switching speed of larger grain-size samples with little or no increase of coercive force. © 1969 The American Institute of Physics.
