THE THERMAL EXPANSION OF COPPER AT LOW TEMPERATURES,

Abstract

The thermal expansion of copper has been determined at temperatures down to 2 K by means of an electrical capacitance technique. By measuring three-terminal capacitances in a ratio-transformer bridge length changes smaller than 10 to the minus 9 power cm can be detected in the capacitor-expansion cell. The linear expansion coefficient is given for below 10 K. These terms, identified respectively as electronic (e) and lattice (l) in origin, lead to the following values of the Gruneisen parameter: gamma sub e = 0.63=0.06, gamma sub l = 1.72=0.03 (= gamma sub 0). Gamma sub e is compared with a theoretical free-electron value of 2/3, and the low temperature value of gamma sub e is compared with values of 1.75 to 1.77 calculated from elastic constants. At room temperature gamma (approximately = gamma sub infinity) is 2.00, so that gamma sub infinity-gamma sub 0 approximately = 0.28, which agrees well with the theoretical estimates of Barron for a close-packed cubic lattice. (Author)

Document Details

Document Type
Technical Report
Publication Date
Dec 05, 1963
Accession Number
AD0611968

Entities

People

  • G. K. White
  • R. D. Mccammon
  • R. H. Carr

Tags

DTIC Thesaurus Topics

  • Capacitance
  • Capacitors
  • Crystal Lattices
  • Cubic Lattices
  • Electrons
  • Free Electrons
  • Gruneisen Parameter
  • Low Temperature
  • Physical Sciences
  • Thermal Expansion

Readers

  • Analytical Mechanics
  • Electrical Engineering
  • Materials Science and Engineering.

Technology Areas

  • Microelectronics