Aliovalent Substitution in 1144 Iron Based Superconductors: Effect on Structure and Superconducting Properties

• Published in: IEEE transactions on applied superconductivity Vol. 32; no. 4; pp. 1 - 5
• Main Authors: Masi, A., Duchenko, A., Armenio, A. Angrisani, Augieri, A., Bellusci, M., Celentano, G., Montereali, M. R., Rizzo, F., Rufoloni, A., Vannozzi, A., Varsano, F.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Carrier density; Compounds; Critical temperature; Ions; Iron; Lattices; pnictides; Powders; Strontium; Substitutes; superconducting materials; superconducting materials growth; Superconductors; Temperature; Temperature measurement; Transition temperature
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2021.3138955

Ca/K-1144 compounds have been described widely in literature as stoichiometric compounds, with a Ca:K ratio equal to unity. In this work, we demonstrate that Sr ions can substitute K ions in the 1144 lattice. Polycrystalline samples were produced via a mechanochemically assisted synthesis route. Sr substitution in the Ca/K compound leads to a shortening of its c axis, while no differences are appreciable from the morphological point of view. The CaK 0.9 Sr 0.1 Fe 4 As 4 compound is characterized by a slightly reduced critical temperature of approximately 31 K, with respect to the 35 K of the pristine compound. The role of lattice distortion carrier concentration or structural disorder that may be accounted for the reduction of critical temperature is here discussed.