Pinning and the mixed-state thermomagnetic transport properties ofYBa2Cu3O7−δ
| Autor: | A. W. Smith, T. W. Clinton, C. J. Lobb, Mandava Rajeswari, Wu Liu, X. Jiang, R. L. Greene |
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| Rok vydání: | 1996 |
| Předmět: | |
| Zdroj: | Physical Review B. 54:R9670-R9673 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.54.r9670 |
| Popis: | We have studied the role of pinning in the mixed-state thermomagnetic transport properties of $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$. We demonstrate the pinning independence of the transport entropy ${S}_{\ensuremath{\varphi}}$, and its consequent scaling within an anisotropic mass model. Due to the anisotropy of $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ the extrinsic pinning strength effectively decreases as we rotate the magnetic field into the $\mathrm{ab}$ plane. The Nernst ($\frac{{E}_{y}}{{\ensuremath{\nabla}}_{x}T}$) and Seebeck ($\frac{{E}_{x}}{{\ensuremath{\nabla}}_{x}T}$) effects are enhanced as we reduce the effective pinning, yet the transport entropy ${S}_{\ensuremath{\varphi}}\ensuremath{\propto}\frac{(\frac{{E}_{y}}{{\ensuremath{\nabla}}_{x}T})}{{\ensuremath{\rho}}_{\mathrm{xx}}}$, the ratio of the Nernst and Seebeck signals, and the ratio of Seebeck and longitudinal resistivity ${\ensuremath{\rho}}_{\mathrm{xx}}$ are unchanged, similar to the pinning independence observed for the Hall conductivity ${\ensuremath{\sigma}}_{\mathrm{xy}}$. These results can be explained within a simple phenomenological model of vortex dynamics. |
| Databáze: | OpenAIRE |
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