Switching magnetic order at an Fe/BaTiO3 interface on and off: Impact on hybrid magnetic-ferroelectric tunnel junctions

Interfacial magnetoelectric coupling for electrically altering the magnetization of ferromagnetic electrodes is a viable path to achieve the electrical writing of the magnetic information in spintronic devices. Exploiting the piezoelectric behavior of a ferroelectric material (FE) in contact with a ferromagnetic (FM) thin film, the electric control of the magnetic anisotropies can be achieved. However, strain-mediated methods seems hardly suitable for integration in spintronic devices, where the piezoelectric activity of a FE layer would be inhibited by the growth on a substrate. This is the reason why there is a growing interest towards “purely electric” magnetoelectric effects. For the paradigmatic Fe/BaTiO₃ (BTO) system, sizable changes of the interfacial Fe magnetic moment upon reversal of the dielectric polarization of BTO have been predicted, and sizable magneto-electric effects have been observed in nanometric hybrid magnetic-ferroelectric tunneling junctions. Nevertheless, so far a clear understanding of the basic physical mechanisms leading to such a macroscopic effect is still lacking.