Domain Structure Formation And Evolution In Epitaxial Exchange-Biased Nife Films With Dislocation Slip Planes

The effect of dislocations on formation the magnetic structure and the elementary events of magnetization reversal processes in epitaxial thin exchange-biased NiFe(100 angstrom)/NiO(500 angstrom) bilayers with [110] or [100] unidirectional anisotropy have been investigated using the magneto-optic indicator film technique. The dislocations have been revealed to induce an inhomogeneous distribution of the magnetization vectors on their slip planes. The dislocation slip planes act as domain nucleation and domain wall pinning centers. The dislocations produce a strong local magnetic anisotropy along one of the <010> directions independent of the orientation of the unidirectional anisotropy induced during the film deposition in the rest (dislocation-free) sample area. Taking into account that the NiFe ferromagnetic film has almost zero magnetostriction, the observed effects could be attributed to stresses or/and uncompensated spins near to the dislocations in the antiferromagnetic layer.