As-75 NMR of Ba(Fe0.93Co0.07)(2)As-2 in high magnetic field
| Title | As-75 NMR of Ba(Fe0.93Co0.07)(2)As-2 in high magnetic field |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Authors | Oh S, Mounce AM, Mukhopadhyay S, Halperin WP, Vorontsov AB, Bud'ko SL, Canfield PC, Furukawa Y, Reyes P, Kuhns PL |
| Journal Title | Physical Review B |
| Volume | 83 |
| Pages | 214501 |
| Date Published | 06 |
| Type of Article | Article |
| ISBN Number | 1098-0121 |
| Accession Number | ISI:000291149900003 |
| Keywords | dependence, mixed-state, platinum, relaxation, RESONANCE, spin-diffusion, superconductors, yba2cu3o7 |
| Abstract | The superconducting state of an optimally doped single crystal of Ba(Fe0.93Co0.07)(2)As-2 was investigated by As-75 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 less than or similar to 0.5 T-c, with T-c approximate to 23 K. This is consistent with the extended s-wave state with A(1g) symmetry, but the precise details of the gap structure are harder to resolve. Measurements of the NMR spin-spin relaxation time T-2 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 T-2, consistent with vortex freezing from which we obtain the vortex phase diagram up to H = 28 T. |
| URL | <Go to ISI>://000291149900003 |
| DOI | 10.1103/PhysRevB.83.214501 |
| Alternate Journal | Phys. Rev. B |
