Orbitronics and unconventional spin-orbit torque for next-generation magnetic memory and spin logic devices

Orbital torques can be used to control magnetization, however, their efficacy is strongly dependent on the conversion of the orbital torque to a spin torque, either in the ferromagnet, or a spacer layer. Here Ding et al demonstrate the potential of antiferromagnetic insulators, specifically CoO, as an extremely efficient orbital-to-spin transducer.

GeSn alloys hold promise for spintronics and quantum computing due to their scalable fabrication and spin manipulation capabilities. Here, the authors study a two-dimensional hole gas in a Ge/GeSn quantum well, revealing enhanced spin-orbit interactions and g-factors, providing key insights for designing GeSn-based spintronic devices.

Weyl semimetals with low crystal symmetry, such as TaIrTe4, are known to host large unconventional spin-orbit torques. Here, Pandey et al combine TaIrTe4 with the van der Waals ferromagnet, Fe3GaTe2, and achieve room temperature field-free magnetization switching with an extremely low critical current density.

Recent work has expanded the concept of altermagnets to non-collinear magnetic materials. Here, Hu et al extend this further to non-collinear chiral materials, determining altermagnetic multipolar order parameters and predicting that such materials host large spin-hall and Edelstein effects.

The orbital Hall effect has recently been shown to produce orbital torques, allowing for the efficient driving of magnetization by light metals such as titanium. Here, Taniguchi et al show that orbital currents can also be generated by surface acoustic waves, showing this in a titanium/nickel bilayer.

Orbital torque, arising from the orbital Hall effect, allows for the manipulation of magnetic order. Crucially, many light elements have large orbital Hall effects and therefore large orbital torques. Here, Zhang, Wei, Duan, Chen, and coauthors demonstrate efficient magnetization switching of Fe3GaTe2 using orbital torque.

Magnetoelectric materials allow electric field control over magnetization and modulation of electric polarization using magnetic fields. Here, the magnetoelectric coupling in polymer-based nanocomposites containing different particle sized magnetostrictive fillers gives information on the size-dependent behavior.

Graphene spintronics is promising for low power 2D electronics in classical and quantum computing platforms. Here, quantised conductance in magnetic nanowire-graphene interfaces is reported, demonstrating ballistic injection of spin polarised carriers in a two-dimensional spin-valve transistor.

There has been a recent surge in interest in using the orbital Hall effect to improve switching performance and expand the material options for spin-orbit torque driven magnetic memory. Here, Gupta et al demonstrate a significant improvement switching efficiency through integration of Ru in place of the more standard heavy metal, Pt.

Van der Waals 2D magnetic materials are promising for spintronic devices due to their tunable large anomalous Hall and Nernst angles. Here, the magneto-transport properties of Fe₃GaTe₂ films are investigated under pressure, demonstrating a robust perpendicular magnetic anisotropy at room temperature and an enhancement of the anomalous Hall angle.