NUCLEAR-SPIN COUPLING OF HE-3 TO METALLIC SB AT LOW-TEMPERATURES

We have studied the nuclear spill-lattice relation of powdered metalli c Sb samples immersed in liquid He-3 from approximately 1.25 mK to 150 mK. The nuclear quadrupole resonance absorption signals were determin ed from the free induction decay signals observed for small tipping an gle rf pulses. The results have shown that the Sb nuclear spin lattice relaxation is significantly enhanced with respect to the Korringa rel axation below 100 mK. This is attributed to the modulation of the He-3 -Sb nuclear spin-spin coupling by the quantum zero point motion of the He-3 on the surface of the metallic particles. Similar processes have been reported for liquid He-3 in contact with insulators.