Influence of aging on fishtail-effect in pure and Ag-doped MG-YBCO

D. Lotnyk; R. V. Vovk; M. A. Obolenskii; A. A. Zavgorodniy; J. Kovac; V. Antal; M. Kanuchova; M. Sefcikova; P. Diko; A. Feher

paper

Influence of aging on fishtail-effect in pure and Ag-doped MG-YBCO

arXiv:0911.3678

Abstract

$M (B)$ -curves were experimentally investigated. Fishtail-effect (FE) was observed in MG 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 in a wide temperature range 0.4 $< T / T_{c} <$ 0.8 at the orientation of magnetic field $H ∥ c$ . It was obtained that the influence of bulk pinning on FE is more effective at low temperatures while surface barriers dominates at high temperatures. The value $H_{ma x}$ for Ag-doped crystals is larger than for a pure one that due to the presence of additional pinning centers, above all on silver atoms.

arXiv comment4 pages, 5 figures