Structural and ferromagnetic resonance characteristics of BaFe12O19 films with minimal linewidths

Hexagonal barium ferrite films with thickness between 0.3 and 8 mum were de posited on (0001) oriented Al2O3 using pulsed laser deposition and optimize d growth and annealing conditions. They were characterized by measurements of x-ray diffraction, Rutherford backscattering, magnetization, atomic forc e microscopy and ferromagnetic resonance (FMR) at 58 GHz. The narrowest FMR lines and largest number of spin wave resonances are obtained when the fie ld is perpendicular to the film plane of 0.3 and 0.46 mum films. To quantit atively account for variations with field angle (theta) we assume (i) a str ain-induced anisotropy energy with cos(4) theta dependence and (ii) that th e film should be pictured as a mosaic whose tiles are tilted out of the fil m plane. (C) 2001 American Institute of Physics.