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Title: Crystal growth and annealing study of fragile, non-bulk superconductivity in YFe 2Ge 2

In this study, we investigated the occurrence and nature of superconductivity in single crystals of YFe 2Ge 2 grown out of Sn flux by employing X-ray diffraction, electrical resistivity and specific heat measurements. We found that the residual resistivity ratio (RRR) of single crystals can be greatly improved, reaching as high as ~60, by decanting the crystals from the molten Sn at ~350°C and/or by annealing at temperatures between 550°C and 600°C. We found that the samples with RRR ≳ 34 showed resistive signatures of superconductivity with the onset of the superconducting transition T c ≈ 1.4K. RRR values vary between 35 and 65 with, on average, no systematic change in value T c, indicating that the systematic changes in RRR do not lead to comparable changes in T c. Specific heat measurements on samples that showed the clear resistive signatures of a superconducting transition did not show any signature of a superconducting phase transition, which suggests that the superconductivity observed in this compound is either some sort of filamentary, strain-stabilized superconductivity associated with small amounts of stressed YFe 2Ge 2 (perhaps at twin boundaries or dislocations) or is a second crystallographic phase that is present at level below detectionmore » capability of conventional powder X-ray techniques.« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2]
  1. Iowa State Univ., Ames, IA (United States)
  2. Iowa State Univ., Ames, IA (United States); Ames Lab. (AMES), Ames, IA (United States)
Publication Date:
Report Number(s):
IS-J-8515
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: 95; Journal Issue: 7; Journal ID: ISSN 1478-6435
Publisher:
Taylor & Francis
Research Org:
Ames Lab., Ames, IA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; crystal growth; superconductivity
OSTI Identifier:
1233220