Suppression of Spin Diffusion Near a Micron-Size Ferromagnet

The spin-lattice relaxation rate in a silica sample containing paramagnetic electron spins, was investigated. The large gradients generated near the ferromagnetic tip of a magnetic resonance force microscope (MRFM) were used to investigate and suppress the spin diffusion. It was observed that by controlling the relative tip position, the spin diffusion can be suppressed. The spin-lattice relaxation rates were found to reduce significantly in the presence of large gradients that suppressed the dipolar coupling between adjacent spins.