Voltage-controlled rotation of magnetic anisotropy in the Ni 90Fe 10/BaTiO 3(001) heterostructure

Abstract

In this work, we demonstrate the voltage control of magnetic anisotropy in a strain-mediated Ni 90 Fe 10 /BaTiO 3 (001) heterostructure. In the pristine state of the heterostructure, the magneto-optical Kerr effect measurements show a transcritical hysteresis loop for the Ni 90 Fe 10 film, indicating a weak perpendicular anisotropy. This was further confirmed by X-ray magnetic circular dichroism – photo-emission electron microscopy, revealing stripe domains in this film. X-ray diffraction analysis of the BaTiO 3 substrate under varying electric fields was used to analyze the orientation of ferroelectric domains. These results indicated that BaTiO 3 exhibits two distinct states depending on the applied electric field: one with domains aligned with the electric field and another with random domain orientation when the field is removed. After substrate poling, the Ni 90 Fe 10 layer switches from weak perpendicular anisotropy to an in-plane uniaxial magnetic anisotropy, with the in-plane direction of anisotropy being controllable by 901 through an electric field. This effect is due to an efficient strain transfer from BaTiO 3 to the Ni 90 Fe 10 lattice, induced by ferroelectric polarization, as shown by XRD. Remarkably, this rotation of the magnetic anisotropy leads to an enhanced converse magnetoelectric coupling value of 1.43 ms m 1 , surpassing previously reported values for other BaTiO 3 -based heterostructures by an order of magnitude. These results emphasize the potential of Ni 90 Fe 10 alloys for next-generation magnetoelectric devices.