2021/09/21 by Browne, Alexander J., Strong, Denver P., Cava, Robert. J.
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2109.10043
We report the synthesis of new equimolar high-entropy alloys (HEAs) formed from five or six 4d/5d transition metals that are each from a different Group of the Periodic Table. These include MoReRuRhPt and MoReRuIrPt, which have a valence electron count (VEC) of 8 and crystallise in the hexagonal close-packed (hcp) structure, making them isoelectronic and isostructural to the elements Ru and Os and the high-pressure phase of the well-known HEA CrMnFeCoNi. Analogous HEAs with VECs of 7, 6 and 5 crystallise with multiple phases, which we rationalise using the atomic size difference, δ, and the electronegativity difference, Δχ, of the constituent elements. Finally, we find our hcp and mixed hcp-σ phase HEAs to be superconductors, and compare their critical temperatures to those of isostructural elements and other HEAs that have recently been reported.