Nuclear magnetic resonance of3He adsorbed submonolayers on Grafoil and argon-coated Grafoil. I. Low coverages

✍ Scribed by S. G. Hegde; J. G. Daunt

• Publisher: Springer US
• Year: 1978
• Tongue: English
• Weight: 1023 KB
• Volume: 32
• Category: Article
• ISSN: 0022-2291
• DOI: 10.1007/bf00056657

✦ Synopsis

Continuous-wave (cw) nuclear magnetic resonance measurements have been made at 5.SMHz of 3He adsorbed on Grafoil and on argon (monolayer)-coated Grafoil at coverages x <-0.40 (x = 1 corresponds to one monolayer), in the temperature range 0.35-4.21 K. To determine the fractional coverages, the adsorption area of the Grafoil and the monolayer coverages were determined from observations of argon and 3He adsorption isotherms. The results indicate that the adsorbed 3He is highly mobile and behaves as a two-dimensional nonideal Fermi gas. Relative magnetic susceptibilities determined from the NMR lines indicate that the onset of Fermi degeneracy is delayed by spin-independent -~He-3He interactions, as shown by the fit to the data of the quantum second virial coefficient expansion for the magnetic susceptibility. It is established that the residual (coverageindependent) linewidth is largely determined by spin-diffusion through local field gradients in voids in the Grafoil.

*We use a modified Robinson design developed and constructed by Mr. P. Kanepa, University of Florida,