The effect of the cooling rate on the solidification process of liquid aluminium is studied using a large-scale molecular dynamics method. It is found that there are various types of short-range order (SRO) structures in the liquid, among which the icosahedral (ICO)-like structures are dominant. These SRO structures are in dynamic fluctuation and transform each other. The effect of the cooling rate on the microstructure is very weak at high temperatures and in supercooled liquids, and it appears only below the liquid-solid transition temperature. Fast cooling rates favour the formation of amorphous structures with ICO-like features, while slow cooling rates favour the formation of FCC crystalline structures. Furthermore, FCC and HCP structures can coexist in crystalline structures. It is also found that nanocrystalline aluminium can be achieved at appropriate cooling rates, and its formation mechanism is thoroughly investigated by tracing the evolution of nanoclusters. The arrangement of FCC and HCP atoms in the nanograins displays various twinned structures as observed using visualization analysis, which is different from the layering or phase separation structures observed in the solidification of Lennard-Jones fluids and some metal liquids.

Spin–orbit torques (SOTs) are known to be the most efficient way to manipulate the magnetization direction by electrical currents. While, conventionally, one symmetry component of the SOTs, namely, the damping-like torque, was considered to play a primary role, recently, the significance of the other component, the field-like torque, has been revised, owing to the non-trivial dynamics it can induce in heavy metal/ferromagnet multilayers. In this work, we first discuss the unusual behavior of the field-like SOT in a Ta/CoFeB/Ta/MgO multilayer system with a reduced magnetic anisotropy and demonstrate an energy-efficient approach to manipulate the magnitude of the SOT effective fields. Finally, our results show a possibility to engineer the anisotropy of the field-like SOTs by piezoelectric strain, which can be potentially attractive for application in spintronics.