Other Research Projects
Other Research Interests
There is other ongoing work in the laboratory besides that listed as separate
One project is designed to examine the question of how much 4He might be take up by
the C60 matrix. Earlier work with third sound and quartz crystal microbalances here
concluded that the data was consistent with no 4He entering the C60 matrix for 4He
added to a film of C60 at low temperatures [1,2]. The Kosterlitz-Thouless transition was
observed to behave normally for 4He on the C60 surface, and third sound propagated
normally on the C60 with the surface appearing to have an index of refraction for
third sound about the same as smooth glass microscope slides. Work
crystal microbalances is consistent with our earlier work and
concludes that no more than 0.06 4He
atom per C60 molecule enters
the C60 matrix for dosing done at T = 1.68 K. Recent investigations have involved single-wall carbon
nanotubes arranged in bundles, and have been directed at the adsorption behavior of helium
in such bundles. For nanotubes that have not had their caps removed, it appears that the
adsorption talks place in the interstitials between the tubes and does so with a rather high binding
Another project (which has recently concluded) involved non-linear IV measurements
of polycrystalline YBCO high temperature superconductors [4-10]. Studies were concerned with
the effect of grain size on the exponents. Measurements were taken at selected fixed
temperatures, as a function of current in various values of the magnetic field.
1. K.S. Ketola, S. Wang, A.F. Hebard, and R.B. Hallock, J. Low Temp. Phys. 89, 609 (1992).
2. K.S. Ketola, S. Wang, A.F. Hebard, and R.B. Hallock, Physica B 194-196, 651 (1994).
3. W. Teizer, R.B. Hallock, E. Dujardin and T.
W. Ebbesen), Phys. Rev. Letters 82, 5305 (1999); Erratum: 84, 1844 (2000).
4. W.M. Tiernan, J.M. Madsen, J.C.W.
Chien, B.M. Gong, Y.S. Yang and R.B. Hallock, Physica C 165, 279 (1990).
5. W.M. Tiernan and R.B. Hallock,
Phys. Rev. B 43, 10508 (1991).
6. W.M. Tiernan and R.B. Hallock, Phys. Rev. B 44, 4661 (1991).
7. W.M. Tiernan and R.B. Hallock,
Phys. Rev. B 46 3688 (1992).
8. W.M. Tiernan, R. Joshi and R.B. Hallock,
Phys. Rev. B 48, 3423 (1993).
9. W.M. Tiernan and R.B. Hallock, Phys. Rev. B
49, 9168 (1994).
10. R.J. Joshi, R.B. Hallock, and J.A. Taylor, Phys. Rev. B 55, 9107 (1997).