  The precessional magnetization dynamics of GaMnAs thin films are
characterized by broadband network analyzer ferromagnetic resonance (FMR) in a
coplanar geometry at cryogenic temperatures. The FMR frequencies are
characterized as function of in-plane field angle and field amplitude. Using an
extended Kittel model of the FMR dispersion the magnetic film parameters such
as saturation magnetization and anisotropies are derived. The modification of
the FMR behavior and of the magnetic parameters of the thin film upon annealing
is analyzed.
