Search

Controlling the magnetic anisotropy in magnetic oxides is critical for the development of oxide spintronics. Here we report on the finding of an emergent interfacial magnetism, with unique perpendicular magnetic anisotropy (PMA), at the interface of a half-doped manganite ${\mathrm{La}}_{1/2}{\mathrm{Sr}}_{1/2}\mathrm{Mn}{\mathrm{O}}_{3}$ film on $\mathrm{LaAl}{\mathrm{O}}_{3}$ substrate, through combined electron spin resonance measurements and density functional theory calculations. The interfacial magnetism can be explained by the $3{d}_{3{z}^{2}\ensuremath{-}{r}^{2}}$ orbital-mediated ferromagnetic exchange interaction between Mn ions near the interface, which is enhanced by the compressive strain from the substrate. Our results provide a useful PMA system for possible spintronic applications, as well as atomistic-level insight to the magnetic anisotropy in strained manganite oxide interfaces.

Creating perpendicular fields by spin-orbit torques (SOTs) is an effective way to realize field-free and highly efficient SOT switching for magnetic films with perpendicular magnetic anisotropy (PMA). Here, (1) using a magnetic trilayer composed of a layer with PMA, a spacer, and a layer with in-plane magnetic anisotropy; and (2) by injecting spin currents with the same polarization into the two magnetic layers, we can generate the desired effective perpendicular field through SOT and further utilize this effective field to assist in field-free SOT switching. The SOT efficiency to produce the perpendicular field reaches $2.1\phantom{\rule{0.2em}{0ex}}\mathrm{Oe}/{10}^{10}\phantom{\rule{0.2em}{0ex}}{\mathrm{Am}}^{\ensuremath{-}2}$. This study can be instructive for designing energy-efficient SOT magnetic random-access memories.