Phase diagram of optimally dopedYBa2Cu3O7−δ: Effect of oxygen stoichiometry
| Autor: | R. M. Langan, Louis Taillefer, Robert Gagnon, Sergey N. Gordeev, Aloysius G. M. Jansen, P.A.J. de Groot |
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| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | Physical Review B. 58:14548-14555 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.58.14548 |
| Popis: | Influence of the oxygen stoichiometry on the phase diagram of clean ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ single crystals has been studied in the region of optimal doping $(0.05l\ensuremath{\delta}l0.09).$ Temperature and angular dependencies of magnetoresistance were analyzed for fields of up to 23 T. At low fields a sharp resistivity kink, which is a signature of the first order melting transition, was observed in all the samples studied. This kink, however, disappears when B exceeds the multicritical field ${B}_{\mathrm{mc}}.$ It was found that ${B}_{\mathrm{mc}}$ strongly increases with decreasing \ensuremath{\delta}. We have demonstrated that variations in the oxygen stoichiometry in the range of $0.05l\ensuremath{\delta}l0.09$ do not have a significant effect on intrinsic parameters (such as anisotropy, coherence length, and penetration depth) but lead to a strong increase in entanglement of the vortex lines. We relate the dependence of ${B}_{\mathrm{mc}}$ on \ensuremath{\delta} with entanglement of the vortex lines, which is promoted by their interaction with oxygen vacancies. |
| Databáze: | OpenAIRE |
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