Ferroelectric polarization in antiferromagnetically coupled ferromagnetic film

• Antiferromagnetic coupling (AFC) at interface supports electric polarization in bi-layers
• A variety of magnetic configurations (Bloch, Neel and mixed ones) are realized in AFC bilayers
• Electric polarization changes in a non-monotone way in magnetic field in AFC bi-layers.
• Dependences of electric polarization on magnetic field P(H) have peculiarity of “cavity”-type.

We report the influence of interface antiferromagnetic coupling on magnetoelectric properties of ferromagnetic bi-layers. Electric polarization arising at magnetic ingomogeneity in bi-layered ferromagnetic structure with antiferromagnetic coupling at interface in applied magnetic field has been explored. Diagrams representing dependences of electric polarization on magnetic field P(H) have been constructed for two magnetic field geometries (in-plane and out-of plane fields). It has been found out that P(H) dependences demonstrate non-monotonic behavior. Peculiarities of polarization in an in-plane-oriented magnetic field have been explained by magnetization processes. It has been shown that a variety of magnetic configurations of Bloch, Neel and mixed Bloch–Neel types can be realized in antiferromagnetically coupled film due to cubic anisotropy contribution. In the area of Bloch magnetic configuration electric polarization vanishes. The critical values of magnetic fields suppressing polarization have been estimated.