Doping Dependence of Vortex Regimes in Y$_{1-x}$Pr$_{x}$Ba$_{2}$Cu$_{3}$O$_{7-\delta}$ Single Crystals
| Autor: | Gyawali, P., Sandu, V., Taylor, B. J., Maple, M. B., Almasan, C. C. |
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| Rok vydání: | 2007 |
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| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.77.174504 |
| Popis: | Magnetic relaxation measurements on a series of Y$_{1-x}$Pr$_{x}$Ba$_{2}$Cu$_{3}$O$_{7-\delta}$ ($x = 0.13, 0.34, 0.47$) single crystals were performed over a large field and temperature range in order to investigate the characteristics of the vortex matter across the second magnetization peak (SMP). The magnitude of the SMP varies non-monotonically with the Pr concentration; i.e., the irreversible magnetization normalized by its value at the onset field $H_{on}$ displays a maximum for the $x = 0.34$ single crystal. The two characteristic fields, $H_{on}$ and $H_{sp}$, follow different temperature $T$ dependences: $H_{on} \propto T^{\nu_{on}}$ and $H_{sp} \propto [1-(T/T_{c})^{2}]^{\nu_{sp}}$. The extracted values of the apparent activation energy $U^\ast$ and the creep exponent $\mu$ display a maximum at a field $H_{on} < H^\ast < H_{sp}$. Their field dependences point toward the coexistence of both elastic and plastic creep for $H > H_{on}$. The degree of participation of each creep mechanism is determined by the charge carrier density, which controls both the elastic properties of the vortex matter and the pinning potential. Comment: 7 figures |
| Databáze: | arXiv |
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