  Thin ferromagnetic films with in-plane magnetic anisotropy are promising
materials for obtaining high microwave permeability. The paper reports on the
M\"ossbauer study of the field induced in-plane uniaxial anisotropy in
electro-deposited $FeCo$ alloy films. The $FeCo$ alloy films have been prepared
by electro-deposition method with and without external magnetic field applied
parallel to the film plane during deposition. The vibrating sample magnetometry
and M\"ossbauer spectroscopy measurements at room temperature indicate that the
film deposited in external field shows an in-plane uniaxial anisotropy with an
easy direction coincides with the external field direction and a hard direction
perpendicular to the field direction, whereas the film deposited without
external field doesn't show any in-plane anisotropy. M\"ossbauer spectra taken
in three geometric arrangements show that the magnetic moments are almost
constrained in the film plane for the film deposited with applied magnetic
field. And the magnetic moments are tend to align in the direction of the
applied external magnetic field during deposition, indicating that the observed
anisotropy should be attributed to directional ordering of atomic pairs.
