EXPERIMENTAL-EVIDENCE FOR A RELATIONSHIP BETWEEN LOTGERING INDEX AND FERROMAGNETIC-RESONANCE LINEWIDTH

Samples of polycrystalline barium hexaferrite were prepared by convent ional powder mixing and co-precipitation techniques. Ceramic specimens were then aligned under pressure and either sintered or hot-pressed. Measurements of the ferromagnetic resonance linewidth of the ceramics were made at millimetre-wave frequencies. The linewidths were correlat ed with X-ray diffraction measurements of the Lotgering indices of the materials. A linear relationship was observed between the Lotgering i ndices and the linewidth which has been related to the loss processes present in the hexaferrite.