Observation of a vortex-glass phase in polycrystalline YBa 2 Cu 3 </mml:mrow…
1991; American Physical Society; Volume: 43; Issue: 13 Linguagem: Inglês
10.1103/physrevb.43.10538
ISSN1095-3795
AutoresT. K. Worthington, Eva Olsson, C. S. Nichols, T. M. Shaw, David R. Clarke,
Tópico(s)Theoretical and Computational Physics
ResumoWe report the results of temperature- and field-dependent transport measurements on sintered, polycrystalline samples of ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathit{x}}$. A study of the E-J curves indicates a second-order phase transition, at low current density in the coupling of the grains, that exhibits the scaling behavior predicted for a vortex glass. The ohmic resistance at low current is observed to vanish at a nonzero temperature, and the E-J curves exhibit power-law behavior at that temperature. Below this temperature the E-J curves are consistent with a true critical current with zero linear resistance. The qualitative features of the data and the values of the critical exponents are consistent with the predictions of the vortex-glass theory. Our findings cannot be explained by the predictions of conventional flux-creep models.
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