Normal and Superconducting Heat Capacities of Lanthanum

Phys. Rev. 109, 70 – Published 1 January 1958
A. Berman, M. W. Zemansky, and H. A. Boorse

Abstract

The heat capacities of three samples of lanthanum have been measured in the temperature range 1.6 to to 6.5°K. A four-constant formula was found which represented to high precision the resistance-temperature relation of the carbon composition resistance thermometer from 1.6 to 7.2°K. Two superconducting transitions were found in each sample: one at 4.8°K and the other at 5.9°K. These are associated respectively with the hexagonal close-packed and face-centered cubic modifications of the metal. Below 2.5°K, a magnetic field of 10 000 gauss was found insufficient to quench completely the superconducting phase. The values of the normal heat capacity constants for the purest sample, averaged over the two crystal structures present, were determined by a thermodynamic analysis of the data to be γ=(24.1±0.6)×10-4 cal/mole (°K)2, Θ=142±3°K. The data are further analyzed for evidence of a law of corresponding states among superconductors.

DOI: http://dx.doi.org/10.1103/PhysRev.109.70

  • Received 22 August 1957
  • Published in the issue dated January 1958

© 1958 The American Physical Society

Authors & Affiliations

A. Berman*, M. W. Zemansky, and H. A. Boorse

  • Pupin Physics Laboratories, Columbia University, New York, New York

  • *Present address: Philco Corporation, Tioga and C Streets, Philadelphia 34, Pennsylvania.
  • Permanent address: The City College of New York, New York, New York.
  • Permanent address: Barnard College, Columbia University, New York, New York.

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