FORCE DETECTION OF NUCLEAR-MAGNETIC-RESONANCE

Micromechanical sensing of magnetic force was used to detect nuclear m agnetic resonance with exceptional sensitivity and spatial resolution. With a 900 angstrom thick silicon nitride cantilever capable of detec ting subfemtonewton forces, a single shot sensitivity of 1.6 x 10(13) protons was achieved for an ammonium nitrate sample mounted on the can tilever. A nearby millimeter-size iron particle produced a 600 tesla p er meter magnetic field gradient, resulting in a spatial resolution of 2.6 micrometers in one dimension. These results suggest that magnetic force sensing is a viable approach for enhancing the sensitivity and spatial resolution of nuclear magnetic resonance microimaging.