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Title: The Properties of Helium Adsorbed on graphite : An NMR Study.
Author: Owers-Bradley, J. R.
ISNI:       0000 0001 3462 0775
Awarding Body: University of Sussex
Current Institution: University of Sussex
Date of Award: 1978
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The properties of the helium -3 film adsorbed on the graphite substrates, grafoil and UCAR zyx, have been studied using NMR techniques. Specific heat measurements on the submonolayer film are consistent with the existence of a 2D as at low density and a. 2D solid at high density. At intermediate densities there is a phase in which the adatoms are in registry with the substrate. The relaxation times T1 and T2 have been measured in the above three phases and for some multilayer films as functionsof temperature, Larmor frequancy and field direction. At low temperatures the results indicate that the registered and the high density phases are quantum solids for which the corresponding quantum tunneling frequencies have been evaluated. The transition from order to disorder at registry and the melting of the incomensurate 2D solid have been investigated and thermal activation energies associated with these processes have been deduced from relaxation time data. The magnetic susceptibility of the low density 3He film adsorbed on grafoil has been studied in some detail and the results are found to be in reasonable agreement with a second virial-coefficient analysis.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available