Half-metallic Co-based full-Heusler alloys with perpendicular magnetic anisotropy (PMA), such as Co₂FeAl in contact with MgO, are receiving increased attention recently due to its full spin polarization for high density memory applications. However, the PMA induced by MgO interface can only be realized for very thin magnetic layers (usually below 1.3 nm), which would have strong adverse effects on the material properties of spin polarization, Gilbert damping parameter and magnetic stability. In order to solve this issue, we fabricated oxidized Co₅₀Fe₂₅Al₂₅ (CFAO) films with proper thicknesses without employing the MgO layer. The samples show controllable PMA by tuning the oxygen pressure (P_O2) and CFAO thickness (t_CFAO), large perpendicular anisotropy field of ~8.0 kOe can be achieved at P_O2 = 12% for the sample of t_CFAO= 2.1 nm or at P_O2= 7% for t_CFAO= 2.8 nm. The loss of PMA at thick t_CFAO or high P_O2 results mainly from the formation of large amount of CoFe oxides, which are superparamagnetic at room temperature but become hard magnetic at low temperatures. The magnetic CFAO films, with strong PMA in a relatively wide thickness range and small intrinsic damping parameter below 0.028, would find great applications in developing advanced spintronic devices.

Spin-transfer-driven switching is investigated by micromagnetic simulation in perpendicular spin valve nanopillars with a free layer structure which contains two in-film-plane regions: a main perpendicularly magnetized hard region and a soft nanocore with intrinsic in-plane anisotropy. The temporal magnetization snapshots demonstrate that the current-induced magnetization rotation starts from the nanocore, followed by an incoherent switching process mediated by domain nucleation and expansion. The initial magnetization rotation of nanocore to in-plane direction generates driving force acting on the hard region via exchange coupling, together with locally enhanced spin torque, leading to considerable reduction in both critical current and switching time.

Interfacial exchange coupling and magnetization reversal characteristics in the perpendicular heterostructures consisting of an amorphous ferrimagnetic (FI) Tb_xCo_100–x alloy layer exchange-coupled with a ferromagnetic (FM) [Co/Ni]_N multilayer have been investigated. As compared with pure Tb_xCo_100–x alloy, the magnetization compensation composition of the heterostructures shift to a higher Tb content, implying Co/Ni also serves to compensate the Tb moment in TbCo layer. The net magnetization switching field H_c⊥ and interlayer interfacial coupling field H_ex, are not only sensitive to the magnetization and thickness of the switched Tb_xCo_100–x or [Co/Ni]_N layer, but also to the perpendicular magnetic anisotropy strength of the pinning layer. By tuning the layer structure we achieve simultaneously both large H_c⊥ = 1.31 T and H_ex = 2.19 T. These results, in addition to the fundamental interest, are important to understanding of the interfacial coupling interaction in the FM/FI heterostructures, which could offer the guiding of potential applications in heat-assisted magnetic recording or all-optical switching recording technique.

Spintronic materials with two-dimensional (2D) transition-metal dichalcogenide (TMD)/ferromagnet (FM) interfaces have received a great deal of interest recently due to strong modulation of the magnetic properties, which provide attractive opportunities for magnetic information storage. Here, we demonstrate the strong spin-orbit coupling (SOC) effect and great interfacial tuning of magnetization dynamics in $M{X}_2$/$\mathrm{Co}\text{−}\mathrm{Fe}\text{−}\mathrm{B}$ thin films by means of a time-resolved magneto-optical Kerr approach, where M is chosen as $\mathrm{Mo}$ or $\mathrm{W}$ and X is $\mathrm{S}$ or $\mathrm{Se}$. The significant drop of demagnetization time, ${\tau }_m$, and increase of magnetic damping factor, ${\alpha }_s$, clearly highlight the presence of high interfacial SOC strength in just one monolayer of ${\mathrm{Mo}\mathrm{S}}_2$. Compared with the single $\mathrm{Co}\text{−}\mathrm{Fe}\text{−}\mathrm{B}$ film, the precession frequency, f, is lowered after inserting a $M{X}_2$ layer, suggesting a reduction of the effective magnetization, $4\pi M_{\mathrm{eff}}$, originating from the interfacial d-d hybridization effect. The role of SOC strength on ${\tau }_m$, $M_{\mathrm{eff}}$, and ${\alpha }_s$ is confirmed by using different TMD materials, and thus, demonstrates that the element M plays a dominant role. The samples with ${\mathrm{WS}}_2$ or ${\mathrm{W}\mathrm{Se}}_2$ have much shorter ${\tau }_m$, smaller $M_{\mathrm{eff}}$, and larger ${\alpha }_s$ values due to the strong SOC interaction of heavier atoms. The observed efficient control of dynamic magnetic behavior will further promote the development of TMD/FM materials for practical spintronic applications with ultrafast manipulation speed and low energy consumption.