Interface perpendicular magnetic anisotropy in heterostructures consisting of CoFeB and conductive rock-salt Li-Ti-O

Abstract We investigated interface perpendicular magnetic anisotropy (PMA) in magnetic heterostructures consisting of ferromagnetic metal CoFeB and conductive rock-salt Li-Ti-O (LTO) layers, which can be classified into an unconventional group different from metallic multilayers and tunnel junctions. The rock-salt structure was confirmed by reflection high-energy electron diffraction for the 5 nm thick LTO layers epitaxially grown on a MgO(001) buffer layer. Interface PMA was clearly observed for the LTO/CoFeB heterostructures with post-annealing above 250˚C, and the effective PMA energy density reached 1.18 Merg/cm3 with post-annealing at 300˚C. The LTO layer thickness dependence of the resistance area product and tunnel magnetoresistance showed a clear difference in transport properties between the present LTO/CoFeB and the conventional MgO/CoFeB heterostructures, as evidence for the electrical conductivity of LTO in the LTO/CoFeB heterostructure. The conductive LTO can be used as a new building block for a PMA heterostructure for spintronic devices.