We measure the magnetic damping parameter α in thin film CoFeB and permalloy (Py) nanomagnets at room temperature using ferromagnetic resonance driven by microwave frequency spin-transfer torque. We obtain α CoFeB = 0.014±0.003 and α Py = 0.010±0.002, values comparable to measurements for extended thin films, but significantly less than the effective damping determined previously for similar nanomagnets by fits to time-domain studies of largeangle magnetic excitations and magnetic reversal. The greater damping found for the large amplitude nanomagnet dynamics is attributed to the nonlinear excitation of non-uniform magnetic modes.

Giant spin Hall effect (GSHE) has received significant attention for its potential in future spintronic applications. Spin current via GSHE-based thin films provides an effective and promising means to manipulate magnetization. However, an external in-plane magnetic field is required to consistently switch the perpendicular magnetic moment. We present an approach to realize field-free deterministic perpendicular magnetic switching with a new structure of FM/NM/FM. Our method takes advantage of the large spin Hall angle of transition metal β-W, so that the critical switching current density is only on the order of 106A/cm2 in the absence of magnetic field.

The interfacial Dzyaloshinskii-Moriya interaction (DMI) holds promises for design and control of chiral spin textures in low-dimensional magnets with efficient current-driven dynamics. Recently, an interlayer DMI has been found to exist across magnetic multilayers with a heavy-metal spacer between magnetic layers. This opens the possibility of chirality in these three-dimensional magnetic structures. Here we show the existence of the interlayer DMI in a synthetic antiferromagnetic multilayer with both inversion and in-plane asymmetry. We analyse the interlayer DMI’s effects on the magnetization and the current-induced spin-orbit torque (SOT) switching of magnetization through a combination of experimental and numerical studies. The chiral nature of the interlayer DMI leads to an asymmetric SOT switching of magnetization under an in-plane magnetic field. Our work paves the way for further explorations on controlling chiral magnetizations across magnetic multilayers through SOTs, which can provide a new path in the design of SOT devices.