AUTHOR=Liu Bin , Wu Jifeng , Cui Yanwei , Zhu Qinqing , Xiao Guorui , Wu Siqi , Cao Guanghan , Ren Zhi 

TITLE=Superconductivity in Cubic A15-type V–Nb–Mo–Ir–Pt High-Entropy Alloys

JOURNAL=Frontiers in Physics

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2021.651808

DOI=10.3389/fphy.2021.651808

ISSN=2296-424X

ABSTRACT=<p>We report the crystal structure and superconducting properties of new V<sub>5+2<italic>x</italic></sub>Nb<sub>35−<italic>x</italic></sub>Mo<sub>35−<italic>x</italic></sub>Ir<sub>10</sub>Pt<sub>15</sub> high-entropy alloys (HEAs) for <italic>x</italic> in the range of 0 <inline-formula id="inf1"><mml:math id="minf1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>≤</mml:mo></mml:math></inline-formula><italic>x</italic><inline-formula id="inf2"><mml:math id="minf2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>≤</mml:mo></mml:math></inline-formula> 10. These HEAs are found to crystallize in a cubic A15-type structure and have a weakly coupled, fully gapped superconducting state. A maximum <italic>T</italic><sub>c</sub> of 5.18 K and zero-temperature upper critical field <inline-formula id="inf3"><mml:math id="minf3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>B</mml:mi><mml:mrow><mml:mtext>c</mml:mtext><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula>(0) of 6.4 T are observed at <italic>x</italic> = 0, and both quantities decrease monotonically with the increase of V content <italic>x</italic>. In addition, <italic>T</italic><sub>c</sub> shows an increase with increasing valence electron concentration from 6.4 to 6.5, which is compared with other A15-type HEA and binary superconductors.</p>