2022/07/24 by Jiro Kitagawa, Kazuhisa Hoshi, Kitagawa, Jiro +9 · 4 citations
Engineering · Physics and Astronomy · #Advanced Materials Characterization Techniques #Alloy #Condensed matter physics #Debye model #FOS: Physical sciences #High Entropy Alloys Studies #Lambda #Materials science #Metal and Thin Film Mechanics #Metallurgy #Microstructure #Phonon #Physics #Quantum mechanics #Quinary #Superconductivity #Superconductivity (cond-mat.supr-con) #Vickers hardness test #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.2207.11845
published in arXiv (Cornell University) (Cornell University) · To appear in Journal of Alloys and Compounds
arxiv created 2022/07/24 · openalex publication_date 2022/07/24 · arxiv updated 2022/07/26 · openalex created_date 2022/07/28 · openalex updated_date 2026/08/05
We have found that body-centered cubic (bcc) HfMoNbTiZr is a type-II BCS high-entropy alloy (HEA) superconductor with a superconducting critical temperature of Tc=4.1 K. By employing a Debye temperature θD of 263 K and Tc, the electron-phonon coupling constant λe-p is calculated to be 0.63. The electronic structure calculation revealed band broadening with energy uncertainties due to atomic disorders. The superconducting properties are compared among equiatomic quinary bcc HEA superconductors. Tc decreases with decreasing λe-p, which is negatively correlated with θD. The negative correlation between λe-p and θD would be caused by a shorter phonon lifetime at a higher θD, which is based on phonon broadening due to atomic disorder and the uncertainty principle. The Vickers microhardness was measured for several bcc HEA superconductors. Tc is exceptionally low in a superconductor with relatively high hardness, because the hardness generally increases with increasing θD, and θD is negatively correlated with Tc in the high-entropy state.