Probing Thermal Magnon Current Mediated by Coherent Magnon via Nitrogen-Vacancy Centers in Diamond

Currently, thermally excited magnons are being intensively investigated, owing to their potential in computing devices and thermoelectric conversion technologies. We report the detection of a thermal magnon current propagating magnetic insulator yttrium iron garnet under temperature gradient using quantum sensor: electron spins associated with nitrogen-vacancy (N-V) centers diamond. A is observed as modified Rabi-oscillation frequencies N-V hosted beam-shaped bulk diamond that resonantly coupled coherent over long distance. Additionally, nanodiamond, alteration spin-relaxation rates, depending on applied gradient, nonresonant excitation conditions. The demonstration probing mediated by via spin states serves basis for creating device platform hybridizes caloritronics qubits.