← Back to search

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

T.-H. Kim, R. Jin, L. R. Walker, J. Y. Howe, M. H. Pan, J. F. Wendelken, J. R. Thompson, A. S. Sefat, M. A. McGuire, B. C. Sales, D. Mandrus, A. P. Li

DOI 10.1103/PhysRevB.80.214518 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

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 nonuniform 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 ΔTC=0.2 K. In the nonuniform contrast region, TC is found to vary between 19.6 and 22.2 K with ΔTC 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 nonuniform region. Thus the variations of superconductivity are associated with local compositional change.

Source-reported materials — not catalogue approval

FormulaReported Tc (K)Pressure (GPa)Type
Ba(Fe1-xCox)2As2

Archive — visibility unverified

Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

22.1Pressure not reportedunknown
BaFe1.8Co0.2As2

Archive — visibility unverified

Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

22.1Pressure not reportedunknown

Similar papers