Time-resolved diamond magnetic microscopy of superparamagnetic nanoparticles*

Magnetic nanoparticles have many biomedical applications including hyperthermia for cancer therapy, magnetic resonance imaging, and magnetic relaxation imaging. These applications require that the magnetic nanoparticles have uniform magnetic properties, size and morphology. We report progress on a nitrogen vacancy (NV) center widefield magnetic microscope which measures the Neel relaxation and hysteresis curve of many single magnetic nanoparticles. In addition, we report on progress to correlate these relaxation measurements to particles size via scanning electron microscope (SEM).