Nuclear Magnetic Resonance in LiquidHe3

New Surface Relaxation Mechanism for LiquidH3einHSteenbergen1, Wiegers2, Perenboom3 et al. 1997Phys. Rev. Lett.9370View full textAdd to dashboardCite

“…1 and 2), shows that surface relaxation is not infinitely fast, as assumed by Low and Rorschach [2]. T ex is therefore not determined by t D , contrary to the previous assumption, which is often used to extract T in from T 1 measurements as a function of temperature [1][2][3]. Since T ex is not found to be equal to t D , this naturally explains why T 1 in 3 He-4 He mixture films does not scale with diffusion coefficient D [6].…”

“…However, the spin-lattice relaxation time T 1 measured in an experiment is determined both by T in and by the surface relaxation T s due to interactions of the nuclear spins with magnetic moments at the unavoidable surfaces of the experimental cell. Therefore T in as a function of temperature cannot be determined unambiguously from T 1 [1][2][3], as both T s and T in are a priori unknown and temperature dependent. In this Letter we present measurements of T 1 of liquid 3 He with 0.5% 4 He and 3 He-4 He mixtures as a function of the magnetic field up to 22 T. These data allow unambiguous determination of T in and a detailed study of the surface relaxation time T s , which is clearly found to be described by the classical Bloembergen, Purcell, and Pound theory [4], an observation not reported earlier.…”

Theory of Spin Relaxation by Magnetic Dipole Interaction in a Fermi Liquid: Application toHe3

“…(1) In the collisionless regime, for q>q 0 , we approximate x" D Y the polarization-potential expression of Aldrich and Pines, 2 Xsc^0* °)/Xs/~0( 0 > 0) chosen such as to yield the experimentally determined 4 The temperature broadening 7 of the spectral density Xsc"(#> <o)A> as a function of co, which is neglected in our approximation, is expected to give rise to a small correction only.…”

Spin Polarization of LiquidHe3by Rapid Melting of Polarized Solid

“…They are of the same order of magnitude as observed in liquid 3 He at usual polarizations. 6 The polarization just after the decompression may be estimated by comparison with the signal from the liquid in equilibrium at temperatures below 100 mK. The background signal from 3 He in the surrounding mixing chamber was determined by varying the 3 He pressure in the cell at constant volume and using the susceptibilities in Ref.…”