Low-temperature magnetic resonance force detection

A low-temperature magnetic resonance force microscope (MRFM) has been built and a force sensitivity of 8×10-17 N/√Hz has been achieved using a single-crystal silicon cantilever with a Q of 200 000 at 6 K. Nuclear magnetic resonance (NMR) of 19F was measured via force detection in a 1% Nd-doped CaF2 sample mounted on the cantilever. Cyclic adiabatic inversion of the 19F nuclear spins was performed using a frequency modulated radio frequency field at 100 MHz, resulting in an oscillatory magnetic force that excited the cantilever vibration. NMR force signals were measured in the temperature range between 12 and 40 K. The MRFM technique was also used to measure some basic NMR properties such as spin-lattice relaxation time. © 1996 American Vacuum Society.