A theoretical investigation of the effect of the oblique anisotropy axis on the ferromagnetic resonance linewidth

The effect of the oblique anisotropy axis on the ferromagnetic resonance (F MR) linewidth in a thin film is studied theoretically. The angular dependen ce of the frequency linewidth is investigated in the plane containing the a nisotropy axis and in the film plane. The effect of the tilt angle on the f requency linewidth is shown. Some unusual broadening of the lines in the FM R spectra and certain features of the variation of the frequency linewidth Delta f with field orientation and field intensity could be interpreted as being due to the fact that the magnetocrystalline anisotropy axis, i.e., th e easy or hard direction of the magnetization, is tilted from the normal wi th an angle delta. The tilt angle das well as the Gilbert damping coefficie nt alpha can be deduced from experimental data through this analysis. (C) 1 999 American Institute of Physics. [S0021-8979(99)08115-3].