magnons to NV center spins*

The application of a rf magnetic field in magnetic materials yield the creation of magnons (spin waves) [1]. For the organic V[TCNE]_x≈2 ferrimagnetic material [2], those magnons are found to have very long spin lifetime, thus enhancing the practical chances for applications. In our work, these excitations are coherent coupled – through the magnon fringe fields – to the spin of a Nitrogen-Vacancy (NV) center within a diamond substrate, placed below our magnetic structure. Interestingly, this coherent coupling has the potential to solve the problem of the communication between local qubits at low temperatures and optical photons, a necessary ingredient for networking and quantum communication. Here, we calculate the magnon spectrum, fringe fields and magnetizations profiles for V[TCNE]_x≈2 disks. In addition, we also derive an effective Hamiltonian describing the coupling between NV center spins and magnons. We calculate the realistic effective Hamiltonian parameters, e.g., the spin-magnon coupling, for different physical setups.


[1] R. W. Damon et al., J. Phys. Chem. Solids 19, 308 (1961).
[2] Na Zhu et. al., Appl. Phys. Lett. 109, 082402 (2016)