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Title: Physical properties and electronic structure of La 3Co and La 3Ni intermetallic superconductors

La 3Co and La 3Ni are reported superconductors with transition temperatures of 4.5 and 6 K, respectively. In this work, we reinvestigate the physical properties of these two intermetallic compounds with magnetic susceptibility χ, specific heat C p and electrical resistivity ρ measurements down to 1.9 K. Although bulk superconductivity is confirmed in La 3Co, as observed previously, only a trace of it is found in La3Ni, indicating that the superconductivity in La 3Ni originates from an impurity phase. Superconducting state parameters for La 3Co, including lower and upper critical fields and the superconducting gap, are estimated. Results of the theoretical calculations of the electronic structure for both materials are also presented, and comparison of the Fermi level location in La 3Co versus La 3Ni explains its larger superconducting T c. A major discrepancy between band structure calculations and the experimentally measured Sommerfeld coefficient is found. The measured electronic density of states is about 2.5 times larger than the theoretical value for La 3Co. This effect cannot be explained by the electron-phonon interaction alone. Renormalization of γ, as well as an ~T 2 behavior of the resistivity, suggests the presence of spin fluctuations in both systems.
Authors:
ORCiD logo [1] ;  [1] ;  [1] ; ORCiD logo [2] ; ORCiD logo [1] ; ORCiD logo [3] ;  [1]
  1. Gdansk Univ. of Technology (Poland). Faculty of Applied Physics and Mathematics
  2. AGH Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LA-UR-16-21372
Journal ID: ISSN 0921-4534
Grant/Contract Number:
AC52-06NA25396; DEC-2012/07/E/ST3/00584
Type:
Accepted Manuscript
Journal Name:
Physica. C, Superconductivity
Additional Journal Information:
Journal Volume: 528; Journal Issue: C; Journal ID: ISSN 0921-4534
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC); National Science Centre (Poland); Ministry of Science and Higher Education (Poland)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; superconductivity; Intermetallic compounds; Band structure calculations
OSTI Identifier:
1458929
Alternate Identifier(s):
OSTI ID: 1396976