A theoretically designed van der Waals ferromagnet Fe ₄ GeTe ₂ is synthesized and shows the nearly room temperature ferromagnetism.

Thinning films induces ferroelectricity: Thin ferroelectric films are needed in computers and medical devices. However, traditional ferroelectric films typically become less and less polarized the thinner the films become. Instead of using a good ferroelectric and making it thinner, Lee et al. started with SrTiO ³ , which in its bulk form is not ferroelectric. This material does have naturally occurring nanosized polarized regions. and when the thickness of the SrTiO ₃ films reaches the typical size of these regions, the whole film aligns and becomes ferroelectric. Science , this issue p. 1314

Separating structure and electrons in VO ₂: Above 341 kelvin—not far from room temperature—bulk vanadium dioxide (VO ₂ ) is a metal. But as soon as the material is cooled below 341 kelvin, VO ₂ turns into an insulator and, at the same time, changes its crystal structure from rutile to monoclinic. Lee et al. studied the peculiar behavior of a heterostructure consisting of a layer of VO ₂ placed underneath a layer of the same material that has a bit less oxygen. In the VO ₂ layer, the structural transition occurred at a higher temperature than the metal-insulator transition. In between those two temperatures, VO ₂ was a metal with a monoclinic structure—a combination that does not occur in the absence of the adjoining oxygen-poor layer. Science , this issue p. 1037

The interconversion of charge and spin currents via spin-Hall effect is essential for spintronics. Energy-efficient and deterministic switching of magnetization can be achieved when spin polarizations of these spin currents are collinear with the magnetization. However, symmetry conditions generally restrict spin polarizations to be orthogonal to both the charge and spin flows. Spin polarizations can deviate from such direction in nonmagnetic materials only when the crystalline symmetry is reduced. Here, we show control of the spin polarization direction by using a non-collinear antiferromagnet Mn₃GaN, in which the triangular spin structure creates a low magnetic symmetry while maintaining a high crystalline symmetry. We demonstrate that epitaxial Mn₃GaN/permalloy heterostructures can generate unconventional spin-orbit torques at room temperature corresponding to out-of-plane and Dresselhaus-like spin polarizations which are forbidden in any sample with two-fold rotational symmetry. Our results demonstrate an approach based on spin-structure design for controlling spin-orbit torque, enabling high-efficient antiferromagnetic spintronics.