Electric Control of Magnetic Exchange in a Molecular Spin Triangle

Materials showing spin-electric (SE) effects are a subclass of magnetoelectric materials. Spin-electric effect allows for electric control of spins. Significant advantages are expected from its achievement in quantum information technology, as a faster, energetically more convenient - since based on electric fields rather than on electric current- and more space-confined spin manipulation with respect to the standard approach based on the magnetic field.

The Electric Field Modulated Electron Paramagnetic Resonance (EFM-EPR), a recently implemented technique in our lab,[1] which allows performing EPR under an electric field, has been proven to be very effective for the in-depth comprehension of the spin-electric effects in magnetic molecules.[2]

Theoretical investigations have highlighted the relevance of triangles of antiferromagnetically coupled half-integer spins [3], in which the electric field can affect the exchange coupling having, therefore, no effect on the spin coherence.

We have in depth investigated the SE effect on a Cu₃ trimer. The anisotropy of the magnetic response to the electric field direction with respect to the crystal orientation was addressed, and comprehensive ab initio and DFT calculations were performed to unravel its origin. We demonstrated that when the electric field is applied in the plane of the triangle, the dominant contribution to the observed SE signal arises from a variation of the isotropic exchange interaction.[4] Moreover, we have revealed a SE effect on a Cr₃ antiferromagnetic spin triangle with a sizeble Dzyaloshinskii–Moriya interaction. [5]