Electrical and thermal cycling of the magnetic anisotropy between out-of-plane and in-plane in Ni90Fe10/BaTiO3 (001) multiferroics

The study investigates the manipulation of the magnetic anisotropy in a thick (1 mu m) Ni90Fe10 layer electrodeposited on a ferroelectric BaTiO3(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 BaTiO3 substrate, the magnetic anisotropy switches to in-plane with a strong uniaxial behavior. The perpendicular magnetic anisotropy can be recovered by mild thermal annealing above the BaTiO3 tetragonal 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 hybrid lead-free magnetoelectric Ni90Fe10/BaTiO3 heterostructures from perpendicular to in-plane.