Synthesis and Thermal Stability Studies of CaFe 4 As 3

• Published in: European journal of inorganic chemistry 2011-09, Vol.2011 (26), p.3920-3925
• Main Authors: Yi, Tanghong, Dioguardi, Adam P., Klavins, Peter, Curro, Nicholas J., Zhao, Liang L., Morosan, E., Kauzlarich, Susan M.
• Format: Article
• Language: English
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201100349

CaFe 4 As 3 is a new intermetallic structure type that can be described as a framework comprising of FeAs 4 tetrahedra. The structure has similarities to the 1‐2‐2 superconducting phase in that the Fe/As network is related to the ThCr 2 Si 2 structure. In addition, this phase shows magnetic transitions associated with spin density waves. This phase was prepared from a Sn flux, and it has recently been reported that further expansion of this structure type via chemical substitution is limited. We have developed a solid‐state synthesis route for the preparation of CaFe 4 As 3 that involves reacting a stoichiometric combination of the constituent elements. The thermal stability of this material was investigated over the 298–1473 K temperature range. An initial investigation of the Sn grown CaFe 4 As 3 crystals showed that residual Sn that was present on the surface of the crystals reacted with the crystals at temperatures above 1173 K to form new phases. A thermal stability study of Sn‐free CaFe 4 As 3 indicated that it decomposed to give CaFe 2 As 2 and Fe 2 As. The thermal behavior of CaFe 2 As 2 was also investigated and the data showed that it can also form CaFe 4 As 3 at high temperatures. The solid‐state synthesis route presented herein and additional solid solution studies may provide opportunities for the prepartion of materials with this structure type with improved electronic properties.