The discovery of superconductivity at 26 K in an iron-arsenide layered compound LaFeAsO1-xFx, has initiated the active research in the field of solid state chemistry and condensed matter physics. Ternary iron arsenide, BaFe2As2 with ThCr2Si2-type structure, is one of the non-superconducting parent compounds, which becomes superconducting upon partial substitution of potassium for barium with maximum Tc of 38 K, or partial substitution of Co or Ni for Fe with maximum Tc of 24 K. Several properties of iron-based superconductors make them attractive candidates for practical applications, once facile methods of wire and tape fabrication are developed. We have previously reported on a facile synthesis method starting from barium and/or potassium hydrides as reactive precursors for the synthesis of BaFe2As2-type compounds in bulk. The hydride synthetic route provides uniform mixing of the starting materials allowing for the lower synthesis temperatures and faster reactions. Hydrogen, which evolves upon hydride decomposition, provides reducing atmosphere facilitating preparation of oxygen-free powders. This synthesis method is also faster and easier compared to solid state reaction between the constituent elements, leading to fine powders with no parasitic impurities, such as unreacted FeAs or elemental Fe and As. In the current work the hydride route is further extended towards the preparation of BaFe2As2 doped with 3d-transtion metals, such as Co and Ni. We have also explored the hydride route for a one-step synthesis and consolidation of doped BaFe2As2 via reactive spark plasma sintering (SPS). This process allows for in-situ consolidation of superconducting powders into desirable shapes in 10-30 min. The influence of the synthetic conditions on the composition and properties of the produced samples will be discussed in the detail.

Hydride route for the synthesis of 122 iron arsenide superconductors

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.