NV Diamond Based Broadband Readout of FMR from Organic Magnetic V[TCNE]₂ Thin Film

Low damping magnetic thin films will play a key role in realizing nanoscale spin based computational elements. Organic-based magnetic films have shown high-quality resonance properties which rival the best oxides, and can be deposited across a wide range of substrates. A local probe of magnetic resonance is desirable for nanoscale characterization since inductive based techniques typically require large samples and can be spatially insensitive. The Nitrogen-Vacancy (NV) defect in diamond can serve as a platform for local, broadband, optical readout of magnetic resonance from a proximal magnetic film. We report broadband optically detected ferromagnetic resonance (ODFMR) from a micron-thick layer of the high quality organic-based ferrimagnet Vanadium Tetracyanoethylene (V[TCNE]₂) grown on a diamond substrate. The locally probed FMR exhibits linewidths on the order of 1 Gauss, indicating both the high quality of the VTCNE on the micron scale and of the ability of the NV as a sensor for low damping materials. This work demonstrates the utility of the NV center to measure FMR of low Ms and organic systems.