Electron Spin Resonance of Nanoscale Materials using Nitrogen Vacancy Ensembles in Diamond

Nitrogen vacancies (NVs) in diamond are quantum defects with long coherence times, yielding extreme sensitivity to magnetic field and making them excellent magnetic sensors for nanomaterials. In this presentation, we demonstrate NV electron spin resonance (NV-ESR) and integrate nanoparticles onto the surface of diamond at various densities toward measuring nanomaterial properties using NV-ESR. Using T1 relaxometry, we demonstrate NV-ESR with the detection of g=2 electrons trapped at the surface of a diamond implanted at the surface with 20 nm of nitrogen and NV-activated. Methods for integrating superparamagnetic iron-oxide nanoparticles (SPIONs) such as wick deposition, PDMS stamping, and spin deposition are next explored, to calibrate reproducible density-controlled deposition. Submicron-resolved magnetic characterization of SPIONs could yield new magnetic interaction information, resulting in improvements to SPIONs as markers for enhanced MRI sensitivity. With the demonstration of NV-ESR and NP integration, we prepare a diamond slab half-covered with NPs for NV magnetometry.