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

TL;DR

This study investigates how aging affects the fishtail effect in pure and silver-doped MG-YBCO superconductors, revealing temperature-dependent pinning mechanisms and the impact of silver doping on magnetic properties.

Contribution

It provides new insights into the influence of aging and silver doping on the fishtail effect and pinning mechanisms in MG-YBCO superconductors.

Findings

Fishtail effect observed across a wide temperature range.

Bulk pinning dominates at low temperatures, surface barriers at high temperatures.

Silver doping increases the maximum magnetic field $H_{max}$ due to additional pinning centers.

Abstract

$M(B)$-curves were experimentally investigated. Fishtail-effect (FE) was observed in MG YBa$_2$Cu$_3$O$_{7-\delta}$ and YBa$_2$(Cu$_{1-x}$Ag$_x$)$_3$O$_{7-\delta}$ (at $x \approx$ 0.02) crystals in a wide temperature range 0.4 $<T/T_c<$ 0.8 at the orientation of magnetic field $\textbf{H}\parallel c$. 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 $H_{max}$ 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.