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Title: Resolution of the discrepancy between the variation of the physical properties of Ce1-xYbxCoIn5 single crystals and thin films with Yb composition

The extraordinary electronic phenomena including an Yb valence transition, a change in Fermi surface topology, and suppression of the heavy fermion quantum critical field at a nominal concentration x≈0.2 have been found in the Ce1-xYbxCoIn5 system. These phenomena have no discernable effect on the unconventional superconductivity and normal-state non-Fermi liquid behaviour that occur over a broad range of x up to ~0.8. However, the variation of the coherence temperature T* and the superconducting critical temperature Tc with nominal Yb concentration x for bulk single crystals is much weaker than that of thin films. To determine whether differences in the actual Yb concentration of bulk single crystals and thin film samples might be responsible for these discrepancies, we employed Vegard’s law and the spectroscopically determined values of the valences of Ce and Yb as a function of x to determine the actual composition xact of bulk single crystals. This analysis is supported by energy-dispersive X-ray spectroscopy, wavelength-dispersive X-ray spectroscopy, and transmission X-ray absorption edge spectroscopy measurements. The actual composition xact is found to be about one-third of the nominal concentration x up to x~0.5, and resolves the discrepancy between the variation of the physical properties of Ce1-xYbxCoIn5 single crystals and thinmore » films with Yb concentration.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [2] ;  [4] ;  [4] ;  [5] ;  [6] ;  [7] ;  [1]
  1. Univ. of California, San Diego, La Jolla, CA (United States)
  2. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
  3. Ames Lab., Ames, IA (United States)
  4. Univ. of California, Santa Cruz, CA (United States)
  5. Fudan Univ., Shanghai (China)
  6. Florida State Univ., Tallahassee, FL (United States)
  7. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
OSTI Identifier:
1225533
Report Number(s):
IS-J--8546
Journal ID: ISSN 1478-6435
Grant/Contract Number:
AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Philosophical Magazine (2003, Print)
Additional Journal Information:
Journal Name: Philosophical Magazine (2003, Print); Journal Volume: 94; Journal Issue: 36; Journal ID: ISSN 1478-6435
Publisher:
Taylor & Francis
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY chemical substitution; Vegard's law; energy-dispersive X-ray spectroscopy; wavelength dispersive X-ray spectroscopy; transmission X-ray absorption edge spectroscopy; intermediate valence; valence transition; unconventional superconductivity; Kondo lattice; heavy fermion behaviour