Reversible out-of-plane to in-plane magnetic transition by electrical and thermal cycling in Ni${}_{90}$Fe${}_{10}$/BaTiO${}_3$(001)

Abstract

The study investigates the manipulation of the magnetic anisotropy in a thick (1 $\mu$m) Ni${}_{90}$Fe${}_{10}$ layer electrodeposited on a ferroelectric BaTiO${}_3$(001) substrate, using a combination of Magneto-optical Kerr Effect, Photoemission Electron Microscopy with X-ray circular magnetic dichroism and X-ray diffraction. In the as-grown state, the system shows weak perpendicular magnetic anisotropy and characteristic stripe domains. Upon out-of-plane electrical poling of the BaTiO${}_3$ substrate, the magnetic anisotropy switches to in-plane with a strong uniaxial behavior. This change is ascribed to the magnetoelastic effect due to the switching of the BaTiO${}_3$ ferroelectric [001] axis into the sample plane, as evidenced by XRD. The strong mechanical interaction with the thick Ni${}_{90}$Fe${}_{10}$ overlayer prevents the full inversion of the substrate. The perpendicular magnetic anisotropy can be recovered by a mild thermal annealing above the BaTiO${}_3$ tetrahedral to cubic phase transition and can be cycled by repeated electrical poling/thermal annealing. This method opens the path to a reversible control of the magnetic anisotropy in Ni${}_{90}$Fe${}_{10}$/BaTiO${}_3$ heterostructures from perpendicular to in-plane.

Possibly an erroneous interpretation of the data