Co-intercalation of Ammonia molecules between FeSe layers in Ba-doped FeSe superconductor

TL;DR

This study reports the synthesis of a Ba-doped FeSe superconductor with co-intercalated ammonia molecules, maintaining high Tc and shielding fraction, and details its structure using synchrotron X-ray diffraction.

Contribution

It introduces a novel synthesis method using liquid ammonia and reveals the co-intercalation of Ba and NH3 molecules in FeSe layers.

Findings

Optimized Tc of 38.8 K achieved.

Superconducting properties are stable across Ba compositions 0.3 to 0.7.

Structural analysis confirms co-intercalation of Ba and NH3 molecules.

Abstract

We have synthesized a Ba-doped FeSe superconductor using liquid ammonia, and investigated in detail the structure and composition of the Ba-FeSe phase. In the superconducting phase, both the Tc and the shielding fraction are almost unchanged even if the nominal composition of Ba is varied in the region from 0.3 to 0.7. The optimized Tc is 38.8 K. We have determined the structure of the superconducting phase with X-ray powder diffraction (using synchrotron radiation) and here describe the co-intercalation of Ba and NH3 molecules between the FeSe layers.