PROFESSOR
SUNY Chancellor's Award
for Excellence in Teaching
Fellow of American Physical Society

EDUCATION
B.S., Villanova University (1964)
M.S., University of Minnesota (1966)
Ph.D., University of Minnesota (1970)

FOCUS

Liquid ³He and ⁴He manifest a variety of phenomena at low temperatures. Most prominent among these are the realization of superfluid phases and a number of phase transitions. Some of these transitions can be achieved in an environment that has dimensionality less than three. Further, the ability of mixing the two isotopes yields a rich thermodynamic space that extends in pressure-temperature-concentration, and, in the case of ³He, in magnetic field as well. We have worked on a variety of topics in this field, but, most recently, we have focused on the superfluid transition of ⁴He in restricted geometries. In these studies, using suitably constructed experimental cells, we can progressively eliminate one spacial variable at a time. This results in "films," "channels," and "boxes." Phase transitions in any system are strongly modified in these limits. This can be calculated theoretically. For many reasons, superfluid ⁴He is ideally suited for these studies and can be used as a critical test of the theoretical calculations. Our research has been funded by the National Science Foundation since 1976.

SELECTED PROJECTS

• Measurements of the superfluid fraction of ⁴He in restricted geometries using a resonance of the superfluid and the mass loading of a torsional pendulum
• Measurements of heat capacity of ⁴He in restricted geometries using oscillating-temperature calorimetry
• Development of a high-resolution thermometer for use near 2K
• Development of direct wafer bonding of silicon wafers
• Studies of micromachined silicon oscillators for applications to helium films

PUBLICATIONS

• S. Mehta, M. O. Kimball, and F. M. Gasparini. Superfluid transition of ⁴He fortwo-dimensional cross-over, heat capacity, and finite-size scaling. J. of Low Temp. Phys. 114, Nos. 5/6, 467­521 (1999).
• F. M. Gasparini and S. Mehta. Adiabatic fountain resonance. J. of Low Temp. Phys. 110, Nos. 1/2, 293­98 (1998).
• S. Mehta and F. M. Gasparini. Specific heat and scaling of ⁴He confined in a planar geometry. Phys. Rev. Lett. 78:2596 (1997).
• F. M. Gasparini, with C. P. Chen, S. Mehta, E. A. Hoefling, and S. Zelakiewicz. Sorption studies of helium and neon by crystals of C₆₀ and C₇₀. J. of Low Temp. Phys. 102, Nos. 1/2, 31­59 (1996).
• F. M. Gasparini, with I. Rhee. Finite-size scaling of confined helium near T_l.
  In Progress in Low Temperature Physics, Vol. 13, D. F. Brewer ed. (North Holland, 1992) pp. 1­90.

Fig 1 The fraction of ⁴He that is superfluid as function of t=(T_l-T)/T_l, where T_l is the superfluid transition temperature. When helium is confined, 2113 and 483Å in this figure, the superfluid fraction decreases more rapidly than in the case of the "unconfined" bulk sample. This decrease in the superfluid fraction is determined by the ratio of the confining size to the correlation length.