Ultrasound and nuclear magnetism in bulk and confined liquid sup 3 He

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5835388

Engel, B N

Two different experiments on liquid {sup 3}He in open and confined geometries were performed. In the first, the attenuation and velocity of 5 MHz ultra-sound were measured in both the bulk normal and superfluid phases as a function of temperature (0.3 to 30 mK) and pressure (0.3 to 34 bars). The zero temperature limiting behavior was observed in the B-phase superfluid at temperatures below T/{Tc} = 0.4. The velocity was found to return to its ordinary first-sound value as was theoretically expected. Using precise measurements of the difference between the zero-and first-sound velocities, the second symmetric Landau parameter, F{sub 2}{sup s}, was deduced as a function of pressure. In the other experiment, nuclear magnetic resonance (NMR) was used to probe the magnetic susceptibility, {chi}, transverse spin dephasing time, {tau}{sub 2}, and spin-lattice relaxation time, {tau}{sub 1}. Measurements were performed as a function of temperature (0.3 mK to 2K), pressure (0 to 9 bars), and frequency (231,345,462,692, and 924 kHz). The magnetic susceptibility was found to obey a Curie-Weiss law with a pressure-dependent ferromagnetic Weiss temperature. The spin dephasing time was found to be a strong function of temperature at low temperature, with its slope determined by the resonance frequency. This frequency dependence of {tau}{sub 2} was exploited, using a simple model, to obtain the true spin-spin relaxation time, {tau}{sub 2}, as a function of temperature. This was found to obey the same inverse temperature dependence as the susceptibility, diverging at the extrapolated ferromagnetic transition.

• Research Organization: Florida Univ., Gainesville, FL (USA)
• OSTI ID: 5835388
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATTENUATION
CURIE-WEISS LAW
DATA
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FREQUENCY DEPENDENCE
HELIUM 3
HELIUM ISOTOPES
INFORMATION
ISOTOPES
LIGHT NUCLEI
MAGNETIC PROPERTIES
MAGNETIC RESONANCE
MAGNETIC SUSCEPTIBILITY
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
RELAXATION
RELAXATION TIME
RESONANCE
SOUND WAVES
SPIN-LATTICE RELAXATION
STABLE ISOTOPES
SUPERFLUIDITY
TEMPERATURE DEPENDENCE
VELOCITY