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arXiv · 1006.4626

Evolution of the fishtail-effect in pure and Ag-doped MG-YBCO

D. A. Lotnyk·R. V. Vovk·M. A. Obolenskii·A. A. Zavgorodniy·J. Kováč·V. Antal·M. Kaňuchová·M. Šefčiková·P. Diko·A. Feher·A. Chroneos
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Abstract

We report on magnetic measurements carried out in a textured YBa$_2$Cu$_3$O$_{7-δ}$ and YBa$_2$(Cu$_{1-x}$Ag$_x$)$_3$O$_{7-δ}$ (at $x \approx$ 0.02) crystals. The so-called fishtail-effect (FE) or second magnetization peak has been observed in a wide temperature range 0.4~$<T/T_c<$~0.8 for $\textbf{H}\parallel c$. The origin of the FE arises for the competition between surface barrier and bulk pinning. This is confirmed in a non-monotonically behavior of the relaxation rate $R$. The value $H_{max}$ for Ag-doped crystals is larger than for the pure one due to the presence of additional pinning centers, above all on silver atoms.

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D. A. Lotnyk, R. V. Vovk, M. A. Obolenskii, A. A. Zavgorodniy, J. Kováč, V. Antal, M. Kaňuchová, M. Šefčiková, P. Diko, A. Feher, A. Chroneos. 2010-06-23. Evolution of the fishtail-effect in pure and Ag-doped MG-YBCO. https://doi.org/10.1007/s10909-010-0198-z

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