Nuclear magnetic resonance study of normal and superfluid {sup 3}He

Thesis/Dissertation · Thu Dec 31 04:00:00 EST 1992

OSTI ID:114791

Hensley, H H

We report on nuclear magnetic resonance studies of normal and superfluid {sup 3}He. The normal fluid work extended previous measurements of the susceptibility from 30 mK to 3 mK, in order to more accurately determine the limiting value of the susceptibility. We took all the data in a single pressure sweep, from 26 to 0.5 bar. We use these values of the susceptibility along with previously published results for the specific heat to determine the Fermi-liquid parameter F{sub o{sup A}}. We find excellent agreement with the extrapolation of the previous work to lower temperatures. In superfluid {sup 3}He-B we made measurements of the g-shift as a function of susceptibility at a pressure of 1 bar and frequencies of 3.87 and 5.82 MHz. The data were fit to a theory which indicates that the Fermi-liquid parameter F{sub 2{sup A}} has a value of 0.1 at low pressure. This is compared with various other estimates. We also calculate the Landau-Ginsburg parameter {beta}{sub 345} and find poor agreement with other estimates. We also measured the {open_quotes}magic tipping angle{close_quotes} (the tipping angle in superfluid {sup 3}He -B where one expects to see a large change in the precession frequency). Contrary to expectations, we find that it does not change as the sample warms to T{sub c}. While performing these experiments we observed two new and unexpected effects-the existence of a small negative frequency shift for tipping angles between 90{degrees} and 104{degrees}, and the existence of a new mode of ringing with a large (400 Hz) frequency shift, seen at large tipping angles.

• Research Organization: Northwestern Univ., Chicago, IL (United States)
• OSTI ID: 114791
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
FERMI GAS
HELIUM 3
MAGNETIC SUSCEPTIBILITY
NUCLEAR MAGNETIC RESONANCE
SUPERFLUIDITY