Direct experimental study of the effect of dislocations on the magnetization reversal in a quasi-two-dimensional ferromagnet with unidirectional anisotropy

The effect of dislocations on the elementary acts of the magnetization reversal in the epitaxial heterostructure NiFe/NiO/MgO(001) has been studied using the magneto-optical indicator film technique. It has been found that the edge dislocations grouped along the $\langle110\rangle$ slip planes lead to the formation of quasi-one-dimensional domains in the permalloy film with the induced uniaxial anisotropy oriented along these planes the direction of which differs by $90^\circ$ from that of the uniaxial anisotropy in the dislocation-free part of the heterostructure. The micromechanism of the observed effect has been discussed taking into account the effect of dislocations on the orientation of spins in the antiferromagnet and their exchange interaction with the spins of the ferromagnet on the interphase plane.