Low-temperature heat-capacity measurements of /sup 4/He films adsorbed on a disordered substrate

Journal Article · Wed Aug 01 04:00:00 EDT 1979 · Phys. Rev., B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.20.997· OSTI ID:5925167

Tait, R H; Reppy, J D

The heat capacity of submonolayer, monolayer, and multilayer /sup 4/He films adsorbed on a disordered substrate (porous Vycor glass) has been measured in the temperature range 0.08--1.3 K. The distinct regions as a function of coverage were observed: (i) coverages less than 28.6 ..mu..mole m/sup -2/ (approximately 1.5 layers) and (ii) coverages greater than 28.6 ..mu..mole m/sup -2/. Arguments are presented to show that for the low-coverage region the adsorbed helium forms a two-dimensional (2-D) solid with a small number of thermally activated adatoms moving in free-particle-like states on top of this solid layer. Arguments are also presented to show that for the high-coverage region a superfluid /sup 4/He fraction lies on top of this initial 2-D solid below a transition temperature T/sub 0/. Measurements of the heat capacity of /sup 4/He films adsorbed on N/sub 2/-preplated Vycor are presented to show that a precoating serves only to change the thickness of the 2-D solid layer and does not affect the form of the heat-capacity curves.

• Research Organization: Laboratory of Atomic and Solid State Physics, and Materials Science Center, Cornell University, Ithaca, New York 14853
• OSTI ID: 5925167
• Journal Information: Phys. Rev., B: Condens. Matter; (United States), Journal Name: Phys. Rev., B: Condens. Matter; (United States) Vol. 20:3; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
EVEN-EVEN NUCLEI
FILMS
HELIUM 4
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
PHYSICAL PROPERTIES
SORPTIVE PROPERTIES
SPECIFIC HEAT
STABLE ISOTOPES
SUBSTRATES
SUPERFLUIDITY
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
ULTRALOW TEMPERATURE
VYCOR