Also called NiI₂, NiBr₂, NiCl₂, FeCl₂, CoCl₂, VCl₂
Simple salts with surprisingly rich magnetism. In most of them the magnetic moments in each layer line up ferromagnetically while neighbouring layers point opposite ways, but in nickel iodide the moments twist into a spiral, and that spiral makes the crystal electrically polarised: the magnetism itself creates ferroelectricity. A 2022 study reported that this combined order survives down to a single layer, which would make NiI2 a two-dimensional multiferroic; how to prove that optically is still being argued about.
They are coordination polyhedra. Only complete ones are drawn.
Three layers of NiI2 in the CdCl2 arrangement. Each layer is shifted by the same step in the same direction, so the pattern repeats only after three layers: c = 19.63 Å. Cell from Ketelaar, Zeitschrift für Kristallographie 88, 26 (1934); COD 1010056.
Readiness runs lab → prototype → pilot → deployed.
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A frustrated triangular lattice with competing ferromagnetic nearest-neighbour and antiferromagnetic third-neighbour exchange, which in NiI2 produces an incommensurate spiral; spin–orbit coupling on iodine adds bond-dependent anisotropy. The polarisation is usually described by the spin-current (inverse Dzyaloshinskii–Moriya) mechanism for spiral magnets, so models need the full spin texture, not only ordering temperatures.
Work dry: exfoliate and encapsulate in a glovebox. In thin NiI2, second-harmonic generation, linear dichroism and Raman track the multiferroic order, but each can also respond to other kinds of symmetry breaking, so combine several probes and follow them with temperature and thickness. For the chlorides, magnetisation against field shows the field-induced flip of the layers directly.
Low ordering temperatures and air sensitivity keep these salts in the lab. Their interest is as the simplest 2D platforms for electric control of magnetism, the mechanism low-power magnetic memory would need.
The newest items tagged NiI2, FeCl2, CoCl2, from the news feed updated 5 Oct 2026.
We report investigations into a new kind of multiferroic heterostructure consisting of a two-dimensional ferromagnetic 1T-phase FeCl2 monolayer and a sliding-ferroelectric bilayer-GaSe using first principles calculations. In this study, we determine the structural and electronic prop… [Phys. Rev. Materials 10, 074420]…
Low-dimensional multiferroics hold great promise for integrated magnetoelectric devices. Spin spiral state has recently been shown to induce ferroelectricity in single-layer van der Waals (vdW) material NiI2. However, how this state evolves and can be tuned towards the two-dimensional limit remain unclear. Here, we…
In this work, we introduce a class of hybrid-parity sliding multiferroics in which the spontaneous ferroelectric polarization is coupled to certain nonrelativistic spin splitting components through interlayer sliding, allowing these components to be reversibly switched in an electrical way. Symmetry analysis identifies…
Multiferroicity arising from non-collinear spin textures and strong spin-orbit interactions offers a route to magnetoelectric functionality in the monolayer limit. Although theory predicts that the properties of monolayer multiferroics can be tuned by strain, gating, or proximity effects, experimental demonstrations of…
The bond-dependent anisotropic Kitaev interactions are the key for the Kitaev model, which has attracted intense interest for its potential to host quantum-spin-liquid states and fractional excitations. However, experimental realizations of such interactions remain scarce. Here, we investigate the magnetic excitations…
All 20 items tagged NiI₂, FeCl₂, CoCl₂ in the news feed · RSS feed for NiI₂, FeCl₂, CoCl₂