Lattice Relaxation of 4He with 3He Impurities: NMR Studies

[摘要] Measurements of the3He nuclear spin relaxation times of dilute3He impurities in solid4He have been used to explore the unusual dynamics of solid 4He at low temperatures. The3He impurities move through the lattice by quantum mechanical exchange with neighboring4He atoms. Because of the larger zero point motion of the3He atoms, there is an appreciable lattice distortion that accompanies the tunneling3He atom and the tunneling motion depends on the elastic properties of the4He lattice. This motion modulates the3He-3He nuclear dipole- dipole interactions and thus determines the NMR relaxation rates. We compare the observed temperature dependence of the NMR relaxation rates with that expected from the measurements of the shear modulus by Syshchenko et al. [Phys. Rev. Lett. 104, 195301 (2009)].

[发布机构] Department of Physics, University of Massachusetts, Amherst; MA; 01003, United States^1;Department of Physics, University of Florida, Gainesville; FL; 32611, United States^2

[关键词] Dipole dipole interactions;Elastic properties;Lattice distortions;Lattice relaxation;NMR relaxation rates;Nuclear spin relaxation;Quantum mechanical;Temperature dependence