Microwave properties of pulsed laser deposited Sc-doped barium hexaferrite films

The properties of thick BaScxFe12-xO19 (0.3 < x < 0.6) scandium hexaferrite films were measured by static and microwave field techniques. Films were deposited by pulsed laser ablation onto c-plane sapphire at oxygen pressures of 20 and 50 mTorr. Vibrating sample magnetometer measurements as corroborated by x-ray data showed that the films below 3 mu m had easy axis of magnetization (c-axis) normal to the film plane with saturation magnetization values of 3.0-3.8 kG. From the ferrimagnetic resonance frequency versus external magnetic field, we deduced a g value of 1.96 +/- 0.03 and uniaxial anisotropy field of similar to 10 kOe. The ferrimagnetic resonance linewidth for the film thicker than 5 mu m was maximum at 32 GHz and decreased with increasing frequency, indicating evidence for nonuniform magnetic field scattering internally. However, the linewidths were lower for films having thickness below 3 mu m. (C) 2000 American Institute of Physics. [S0021-8979(00)26108-2].