Campus Units
Physics and Astronomy, Ames Laboratory
Document Type
Article
Publication Version
Published Version
Publication Date
6-1-2011
Journal or Book Title
Physical Review B
Volume
83
Issue
21
First Page
214501
DOI
10.1103/PhysRevB.83.214501
Abstract
The superconducting state of an optimally doped single crystal of Ba(Fe0.93Co0.07)2As2 was investigated by 75As NMR in high magnetic fields from 6.4 to 28 T. It was found that the Knight shift is least affected by vortex supercurrents in high magnetic fields H>11 T, revealing slow, possibly higher order than linear, increase with temperature at T≲0.5Tc, with Tc≈23 K. This is consistent with the extended s-wave state with A1g symmetry, but the precise details of the gap structure are harder to resolve. Measurements of the NMR spin-spin relaxation time T2 indicate a strong indirect exchange interaction at all temperatures. Below the superconducting transition temperature, abrupt changes in vortex dynamics lead to an anomalous dip in T2, consistent with vortex freezing from which we obtain the vortex phase diagram up to H=28 T.
Copyright Owner
American Physical Society
Copyright Date
2011
Language
en
File Format
application/pdf
Recommended Citation
Oh, Sangwon; Mounce, A. M.; Mukhopadhyay, S.; Halperin, W. P.; Vorontsov, A. B.; Bud’ko, Sergey L.; Canfield, Paul C.; Furukawa, Y.; Reyes, A. P.; and Kuhns, P. L., "As-75 NMR of Ba(Fe0.93Co0.07)(2)As-2 in high magnetic field" (2011). Physics and Astronomy Publications. 670.
https://lib.dr.iastate.edu/physastro_pubs/670
Comments
This article is published as Oh, Sangwon, A. M. Mounce, S. Mukhopadhyay, William P. Halperin, A. B. Vorontsov, S. L. Bud’ko, P. C. Canfield, Y. Furukawa, A. P. Reyes, and P. L. Kuhns. "As 75 NMR of Ba (Fe 0.93 Co 0.07) 2 As 2 in high magnetic field." Physical Review B 83, no. 21 (2011): 214501. DOI: 10.1103/PhysRevB.83.214501. Posted with permission.