The electric-field–induced “zero-degree domain walls” in ferromagnets

The internal structure of electric-field–induced magnetic topological defects in dielectric magnetic film with inhomogeneous magnetoelectric effect is considered. It is shown that this “zero-degree domain wall” has a complex internal structure with the sense of magnetization rotation and corresponding electric polarity changing twice across the wall. The two possible solutions corresponding to 0° domain walls (the pure cycloidal domain wall and the mixed one) as well as their energies are analyzed. It is shown that the 0° domain wall is a transitional state between the homogeneously magnetized media and the electric-field–induced magnetic domain. The critical field of the domain nucleation obtained from this model is within the range of experimental values of several MV/cm