| Autor: |
W. G. Moulton, K. Asayama, Y. Kitaoka, Y. Kodama, Guo-Qing Zheng, W. G. Clark, Philip L. Kuhns |
| Rok vydání: |
2000 |
| Předmět: |
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| Zdroj: |
Physica B: Condensed Matter. :901-903 |
| ISSN: |
0921-4526 |
| DOI: |
10.1016/s0921-4526(99)01161-8 |
| Popis: |
The responses to the magnetic field ( H ) of the superconductivity and the pseudogap in the underdoped high- T c cuprate YBa 2 Cu 4 O 8 ( T c =74 K ) are reported up to 23.2 T based on NMR measurements. For temperatures T⩽15 K , the H - and T -variation of the 63 Cu nuclear spin-lattice relaxation rate (1/ T 1 ) is 1/ T 1 ∝ TH and also the Knight shift increases with increasing H . We interpret our results as evidence for H -induced quasiparticle states that extend from the d-wave vortex centers with an ungapped spectrum. Even though H =23.2 T reduces T c by 19 K , no effect is seen on the normal-state pseudogap which persists in the temperature region where the superconductivity is destroyed by the field, suggesting that it is a consequence of strong electron correlations. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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