Probing microscopic variations of superconductivity on the surface of Ba(Fe1-xCox)2As2 single crystals

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.80.214518· OSTI ID:969984

Kim, Tae Hwan ^[1]; Jin, Rongying ^[2]; Walker, Larry R ^[1]; Howe, Jane Y ^[1]; Pan, Minghu ^[1]; Wendelken, J F ^[1]; Thompson, James R ^[1]; Sefat, A. S. ^[3]; McGuire, Michael A ^[1]; Sales, Brian C ^[1]; Mandrus, David ^[1]; Li, An-Ping ^[1]

---

1. ORNL
2. Louisiana State University
3. Oak Ridge National Laboratory (ORNL)

The spatially resolved electrical transport properties have been studied on the surface of optimally-doped superconducting Ba(Fe1-xCox)2As2 single crystal by using a four-probe scanning tunneling microscopy. While some non-uniform contrast appears near the edge of the cleaved crystal, the scanning electron microscopy (SEM) reveals mostly uniform contrast. For the regions that showed uniform SEM contrast, a sharp superconducting transition at TC = 22.1 K has been observed with a transition width TC = 0.2 K. In the non-uniform contrast region, TC is found to vary between 19.6 and 22.2 K with TC from 0.3 to 3.2 K. The wavelength dispersive x-ray spectroscopy reveals that Co concentration remains 7.72% in the uniform region, but changes between 7.38% and 7.62% in the non-uniform region. Thus the variations of superconductivity are associated with local compositional change.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences; High Temperature Materials Laboratory
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 969984
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 21 Vol. 80; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
MONOCRYSTALS
SCANNING ELECTRON MICROSCOPY
SCANNING TUNNELING MICROSCOPY
SUPERCONDUCTIVITY
TRANSPORT
WAVELENGTHS
X-RAY SPECTROSCOPY