  Broadband ferromagnetic resonance is measured in single crystalline Fe films
of varying thickness sandwiched between MgO layers. An exhaustive magnetic
characterization of the films (exchange constant, cubic, uniaxial and surface
anisotropies) is enabled by the study of the uniform and the first
perpendicular standing spin wave modes as a function of applied magnetic field
and film thickness. Additional measurements of non-reciprocal spin wave
propagation allow us to separate each of the two interface contributions to the
total surface anisotropy. The results are consistent with the model of a
quasi-bulk film interior and two magnetically different top and bottom
interfaces, a difference ascribed to different oxidation states.
