The manufacture, characterisation and microwave properties of aligned M ferrite fibres

Gel fibres of strontium and barium M ferrite were blow spun from an aqueous inorganic sol and collected as aligned tow blankets. Both were then calcined to 1000 degrees C and characterised using a variety of techniques. The ceramic fibres were shown to be the respective single phase crystalline M ferrites at 1000 degrees C by X-ray diffraction, and compared to standard commercially available M ferrites at this temperature they demonstrated a favourable grain structure of less than 1 mu m. Measurement of the microwave permeability spectra showed both materials exhibiting ferromagnetic resonance frequencies consistent with those reported in the literature. (C) 1998 Elsevier Science B.V. All rights reserved.