Heat treatment effects on the superconducting properties of Ag-doped SrKFeAs compound

TL;DR

This study investigates how annealing temperature affects the superconducting properties of Ag-doped Sr0.6K0.4Fe2As2, finding that annealing at around 900°C enhances critical current density by improving Ag diffusion and grain connectivity.

Contribution

The paper identifies optimal annealing conditions, particularly around 900°C, to improve superconducting performance in Ag-doped Sr0.6K0.4Fe2As2 via a one-step solid reaction method.

Findings

Higher annealing temperature (~900°C) improves Ag diffusion and grain connectivity.

Low-temperature sintering is less effective for Ag-doped samples.

Optimal annealing enhances critical current density Jc.

Abstract

The superconducting properties of polycrystalline Sr0.6K0.4Fe2As2 were strongly influenced by Ag doping (Supercond. Sci. Technol. 23 (2010) 025027). Ag addition is mainly dominated by silver diffusing, so the annealing process is one of the essential factors to achieve high quality Ag doped Sr0.6K0.4Fe2As2. In this paper, the optimal annealing conditions were studied for Ag doped Sr0.6K0.4Fe2As2 bulks prepared by a one-step solid reaction method. It is found that the annealing temperature has a strong influence on the superconducting properties, especially on the critical current density Jc. As a result, higher heat treatment temperature (~900C) is helpful in diffusing Ag and reducing the impurity phase gathered together to improve the grain connectivity. In contrast, low-temperature sintering is counterproductive for Ag doped samples. These results clearly suggest that annealing at ~900C is necessary for obtaining high Jc Ag-doped samples.