Efficient current-driven magnetization switching owing to isotropic magnetism in a highly symmetric 111-oriented Mn₄N epitaxial single layer

We investigated in-plane current-induced magnetization switching in a Mn₄N epitaxial single layer. Efficient magnetization switching was detected via the measurement of anomalous Hall resistivity after the application of current pulses, with a duration of 1 s, to the 111-oriented Mn₄N film compared with a reference 001-oriented Mn₄N film. The threshold current density of magnetization switching with 0.5 s pulse durations, J_c ≈ 1 MA/cm², was relatively low compared with that reported for magnetic tunnel junctions and/or ferromagnet/heavy metal bilayer systems. The relatively low J_c in the 111-oriented film was attributed to the low magnetic anisotropy on the (111) plane of Mn₄N owing to the isotropic crystal symmetry as revealed by x-ray diffraction and transmission electron microscopy as a reduced switching barrier boosts the probability of magnetization switching. It was concluded that manipulation of the magnetic anisotropy based on the crystal orientation is one of the promising approaches to develop materials suitable for application in highly efficient switching devices with Mn₄N layers.