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Eliashberg theory applied to the study of an Nb-Ge series

Abstract

We use strong coupling theory of superconductivity to perform a detailed analysis of the Eliashberg functions {alpha}{sup 2}F({omega}), for thirteen samples of Nb-Ge with critical temperatures ranging from 7.0 K to 21.1K. As critical temperature increases, we analyze the general trends of the electron-phonon coupling parameter {lambda}, of the integral of {alpha}{sup 2}F({omega})``A``, and of other characteristics of {alpha}{sup 2}F({omega}) on the basis of qualitative or empirical criteria. While we find that the samples have in general the behavior expected, a closer analysis points to an overall attenuation in {alpha}{sup 2}F({omega}) of unclear origin. Though the gap edge, {Delta}{sub 0}, appears to be well described by the {alpha}{sup 2}F({omega}) obtained, the thermodynamic critical field agrees poorly with that reproduced by {alpha}{sup 2}F({omega}) in the only case where the necessary (tunneling {alpha}{sup 2}F({omega}), critical field measurements) data are available. Our analysis suggests there is a gross uncertainty in the measured H{sub c}(0). The overall analysis shows that the samples obtained are of enough quality to already give meaningful results upon inversion of the tunneling data. (author). 23 refs, 14 figs, 6 tabs.
Authors:
Baquero, R; [1]  Gutierrez-Ibarra, J; [2]  Kihlstrom, K E [3] 
  1. International Centre for Theoretical Physics, Trieste (Italy)
  2. Universidad Autonoma de Puebla (Mexico). Escuela de Fisica
  3. Westmont College, Santa Barbara, CA (USA). Dept. of Physics
Publication Date:
Jul 01, 1991
Product Type:
Technical Report
Report Number:
IC-91/155
Reference Number:
SCA: 665411; PA: AIX-22:082558; SN: 91000609356
Resource Relation:
Other Information: PBD: Jul 1991
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; SUPERCONDUCTING JUNCTIONS; GORKOV-ELIASHBERG THEORY; CRITICAL FIELD; ELECTRON-PHONON COUPLING; FUNCTIONS; GERMANIUM; NIOBIUM; SUPERCONDUCTIVITY; TRANSITION TEMPERATURE; 665411; BASIC SUPERCONDUCTIVITY STUDIES
OSTI ID:
10105011
Research Organizations:
International Centre for Theoretical Physics (ICTP), Trieste (Italy)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ON: DE92609666; TRN: XA9129675082558
Availability:
OSTI; NTIS (US Sales Only); INIS
Submitting Site:
INIS
Size:
41 p.
Announcement Date:
Jun 30, 2005

Citation Formats

Baquero, R, Gutierrez-Ibarra, J, and Kihlstrom, K E. Eliashberg theory applied to the study of an Nb-Ge series. IAEA: N. p., 1991. Web.
Baquero, R, Gutierrez-Ibarra, J, & Kihlstrom, K E. Eliashberg theory applied to the study of an Nb-Ge series. IAEA.
Baquero, R, Gutierrez-Ibarra, J, and Kihlstrom, K E. 1991. "Eliashberg theory applied to the study of an Nb-Ge series." IAEA.
@misc{etde_10105011,
title = {Eliashberg theory applied to the study of an Nb-Ge series}
author = {Baquero, R, Gutierrez-Ibarra, J, and Kihlstrom, K E}
abstractNote = {We use strong coupling theory of superconductivity to perform a detailed analysis of the Eliashberg functions {alpha}{sup 2}F({omega}), for thirteen samples of Nb-Ge with critical temperatures ranging from 7.0 K to 21.1K. As critical temperature increases, we analyze the general trends of the electron-phonon coupling parameter {lambda}, of the integral of {alpha}{sup 2}F({omega})``A``, and of other characteristics of {alpha}{sup 2}F({omega}) on the basis of qualitative or empirical criteria. While we find that the samples have in general the behavior expected, a closer analysis points to an overall attenuation in {alpha}{sup 2}F({omega}) of unclear origin. Though the gap edge, {Delta}{sub 0}, appears to be well described by the {alpha}{sup 2}F({omega}) obtained, the thermodynamic critical field agrees poorly with that reproduced by {alpha}{sup 2}F({omega}) in the only case where the necessary (tunneling {alpha}{sup 2}F({omega}), critical field measurements) data are available. Our analysis suggests there is a gross uncertainty in the measured H{sub c}(0). The overall analysis shows that the samples obtained are of enough quality to already give meaningful results upon inversion of the tunneling data. (author). 23 refs, 14 figs, 6 tabs.}
place = {IAEA}
year = {1991}
month = {Jul}
}