Spin lifetime in small ensembles of electron spins measured by magnetic resonance force microscopy

Magnetic resonance force microscopy can enable nanoscale imaging of spin lifetime. We report temperature-dependent measurements of the spin correlation time τm of the statistical fluctuations of the spin polarization—the spin noise—of ensembles containing ~100 electron spins by this technique. Magnetomechanical relaxation due to spin-cantilever coupling was controlled and spurious mechanisms that can affect the spin correlation time of the microscopic signal were characterized. These measurements have ramifications for optimizing spin sensitivity, understanding local spin dynamics, and for nanoscale imaging.