Heterojunction-induced magnetic anisotropy and magnetization reversal of Ni wires on LiNbO3 substrate

Highlights: • Zebra-stripe domains are formed in Ni wires perpendicular to the X direction of LiNbO₃. • The heterojunction between Ni and LiNbO₃ induces uniaxial magnetic anisotropy. • The uniaxial magnetic anisotropy is induced parallel to the X direction of substrate. • Micromagnetic simulations can reproduce the zebra-stripe domain structures. • Magnetoresistances provide the understanding of the magnetization reversal. • The anisotropy is estimated to be approximately 3.3 kJ/m³ in this study. We report magnetic domain formation control within micro-scale polycrystalline Ni wires on a single-crystal Y-cut 128° LiNbO₃ substrate. X-ray magnetic circular dichroism photoemission electron microscopy (XCDM-PEEM), micromagnetic simulations, and magnetoresistance (MR) measurements allowed us to estimate the uniaxial magnetic anisotropy induced by the magnetoelastic effect that originated at the interface between each Ni layer and the LiNbO₃ substrate. Comparison of the XMCD-PEEM and MR measurement results shows that the competition between the shape magnetic anisotropy and the uniaxial magnetic anisotropy parallel to the orientation flat (OF) direction of the substrate leads to variations in both the magnetization order and the magnetization reversal process. The uniaxial magnetic anisotropy is estimated to be approximately 3.3 kJ/m³. This heterojunction structure composed of ferromagnetic and ferroelectric layers thus offers alternative ways to produce artificial functional multiferroic materials and devices.