Nanomechanical detection of nuclear magnetic resonance using a silicon nanowire oscillator

The authors report the use of a radio frequency (rf) silicon nanowire mechanical oscillator as a low-temperature nuclear magnetic resonance force sensor to detect the statistical polarization of H-1 spins in polystyrene. To couple the H-1 spins to the nanowire oscillator, a magnetic resonance force detection protocol was developed that utilizes a nanoscale current-carrying wire to produce large time-dependent magnetic field gradients as well as the rf magnetic field. Under operating conditions, the nanowire experienced negligible surface-induced dissipation and exhibited an ultralow force noise near the thermal limit of the oscillator.