Observation of nearly intrinsic ferromagnetic resonance linewidth in BaFe12O19 films deposited by pulsed laser deposition

We report magnetic resonance results on (0.3-8 mum) Mms of c-axis oriented barium ferrite grown by pulsed laser deposition on sapphire substrates. By optimizing the growth and annealing parameters, we have observed numerous ( up to 25) spin wave resonance modes as well as nearly intrinsic ferromagnet ic resonance linewidth of 23 Oe at 58 GHz, when the applied field is parall el to the c axis. On rotation of the field away from the film normal, the l inewidth increases rapidly. This is taken in to account by using a small (0 .3 degrees) spread in the film orientation combined with the conventional f ormula for shape anisotropy. Atomic force microscopy surface roughness meas urements support these considerations.