Simultaneous observation of magnetostatic backward volume wave and surface wave resonances in single crystal barium hexaferrite platelets with in-plane c-axis

Resonances attributed to simultaneous excitation of magnetostatic backward volume waves and surface waves were observed for a platelet of barium hexaferrite with in-plane uniaxial easy direction c-axis. It was shown that backward volume wave resonances can be magnetically tuned over 50-62 GHz with a bias magnetic field of 5.5 kOe, a much smaller bias than in the case of a barium hexaferrite plate with c-axis perpendicular to plane. Theoretical estimates are qualitatively in agreement with the data. Some discrepancies between theory and data are attributed to electromagnetic propagation effects.