Enhanced modulation of magnetization in the Fe3O4/MgO/SrTiO3 heterostructure by electric field

The temperature dependence of the in-plane saturation magnetization of the Fe3O4/MgO/SrTiO3 multiferroic heterostructure is investigated under various electric fields. The MgO interlayer is utilized to introduce oxygen vacancies into the heterostructure. Compared with the case of the Fe3O4/SrTiO3, a different variation trend of the magnetization has been attained in the Fe3O4/MgO/SrTiO3 since the oxygen vacancies accumulate on the Fe3O4 layer at the negative electric field. The magnetoelectric coupling coefficient of the Fe3O4/MgO/SrTiO3 at an electric field of −500 kV/cm is 1.21 Oe·cm/kV, 42% larger than that of the Fe3O4/SrTiO3. The distribution of oxygen vacancies controlled by the electric field plays an important role in the modulation of magnetization. The insertion of the MgO layer is responsible for the larger magnetoelectric response.