Interfacial orbital preferential occupation induced controllable uniaxial magnetic anisotropy observed in Ni/NiO(110) heterostructures

Abstract

Condensed matter physics: unexpected magnetic anisotropy emerges in a heterostructure An unexpected magnetic anisotropy emerges at the interface of nickel and nickel oxide, which is attributed to the anisotropic orbital occupation of interfacial nickel ions. A team led by Yuan-Hua Lin at the Tsinghua University and collaborators at the University of Tokyo and Northeastern University investigated the magnetic properties of a Ni/NiO heterostructure grown on SrTiO3 substrate. They observed an unexpected magnetic anisotropy along an in-plane axis at the Ni and NiO (110) interface. By measuring the thickness and temperature dependence, they excluded the interfacial exchange coupling as a mechanism. Instead, further local magnetic measurements revealed that an anisotropic orbital occupancy of interfacial nickel ions drove the emergence of such a magnetic anisotropy. This result may provide a helpful insight to manipulate this magnetic anisotropy in spintronic applications by strain engineering.