Eliashberg analysis of the specific heat of Nb/sub 0. 75/Zr/sub 0. 25/

Journal Article · Sat Feb 01 00:00:00 EST 1986 · J. Low Temp. Phys.; (United States)

DOI:https://doi.org/10.1007/BF00683466· OSTI ID:5907651

Junod, A; Jorda, J; Muller, J

The specific heat of Nb/sub 0.75/Zr/sub 0.25/ is measured from 1.2 to 50 K in zero magnetic field. A phonon density of states F(..omega..) and a spectral electron--phonon coupling function ..cap alpha../sup 2/(..omega..)F(..omega..) are fitted to the data in the normal state and in the superconducting state. The results are compared with a previous similar analysis of the specific heat of pure Nb and with published tunneling data. It is found that in Nb/sub 0.75/Zr/sub 0.25/, lambda-..mu..* = 1.13, ..omega../sub log/ = 109 K, and N(0) = 0.85 eV/sup -1/ at/sup -1/ spin/sup -1/, compared with the figures 0.84, 146 K, and 0.85 eV/sup -1/ at/sup -1/ spin/sup -1/, respectively, in pure Nb. These data confirm that the increase of T/sub c/ upon the alloying of Nb with Zr is due to phonon softening. They further show that the electronic density of states at the Fermi level is identical in Nb and Nb/sub 0.75/Zr/sub 0.25/. Dimensionless thermodynamic ratios predicted from tunneling data are entirely confirmed, thus confirming the internal consistency of the Eliashberg theory for superconductivity.

• Research Organization: Departement de Physique de la Matiere Condesee, Universite de Geneve, Geneva, Switzerland
• OSTI ID: 5907651
• Journal Information: J. Low Temp. Phys.; (United States), Vol. 62:3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
GORKOV-ELIASHBERG THEORY
ENERGY-LEVEL DENSITY
SPECIFIC HEAT
NIOBIUM ALLOYS
SUPERCONDUCTIVITY
ZIRCONIUM ALLOYS
ELECTRON-PHONON COUPLING
PHONONS
TRANSITION TEMPERATURE
TUNNEL EFFECT
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
PHYSICAL PROPERTIES
QUASI PARTICLES
THERMODYNAMIC PROPERTIES
360104* - Metals & Alloys- Physical Properties
656102 - Solid State Physics- Superconductivity- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena- (-1987)