AUTHOR=Yuan Yuan , Wu Yuan , Luo Huiqian , Wang Zhaosheng , Liang Xue , Yang Zhi , Wang Hui , Liu Xiongjun , Lu Zhaoping 

TITLE=Superconducting Ti15Zr15Nb35Ta35 High-Entropy Alloy With Intermediate Electron-Phonon Coupling

JOURNAL=Frontiers in Materials

VOLUME=5

YEAR=2018

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2018.00072

DOI=10.3389/fmats.2018.00072

ISSN=2296-8016

ABSTRACT=<p>The body-centered cubic (BCC) Ti<sub>15</sub>Zr<sub>15</sub>Nb<sub>35</sub>Ta<sub>35</sub> high-entropy alloy showed superconducting behavior at around 8 K. The electronic specific heat coefficient γ and the lattice specific heat coefficient β were determined to be γ = 9.3 ± 0.1 mJ/mol K<sup>2</sup> and β = 0.28 ± 0.01 mJ/mol K<sup>4</sup>, respectively. It was found that the electronic specific heat <italic>C</italic><sub><italic>es</italic></sub> does follow the exponential behavior of the Bardeen-Cooper-Schrieffer (BCS) theory. Nevertheless, the specific heat jump (Δ<italic>C</italic>/γ<italic>T</italic><sub><italic>c</italic></sub>) at the superconducting transition temperature which was determined to be 1.71 deviates appreciably from that for a weak electron-phonon coupling BCS superconductor. Within the framework of the strong-coupled theory, our analysis suggests that theTi<sub>15</sub>Zr<sub>15</sub>Nb<sub>35</sub>Ta<sub>35</sub> HEA is an intermediate electron-phonon coupled BCS-type superconductor.</p>