J. Mater. Sci. Technol. ›› 2024, Vol. 189: 60-67.DOI: 10.1016/j.jmst.2023.11.040

• Research Article • Previous Articles     Next Articles

Thermal-driven gigantic enhancement in critical current density of high-entropy alloy superconductors

Jihyun Kima, Soon-Gil Jungb,*, Yoonseok Hana, Jin Hee Kimc, Jong-Soo Rhyeec, Sunmog Yeod, Tuson Parka,e,**   

  1. aDepartment of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea;
    bDepartment of Physics Education, Sunchon National University, Suncheon 57922, Republic of Korea;
    cDepartment of Applied Physics and Institute of Natural Sciences, Integrated Education Institute for Frontier Science and Technology (BK 21 Four), Kyung Hee University, Yongin, 17104, Republic of Korea;
    dKorea Multi-purpose Accelerator Complex, Korea Atomic Energy Research Institute, Gyeongju, Gyeongbuk, 38180, Republic of Korea;
    eCenter for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon 16419, Republic of Korea
  • Received:2023-10-07 Revised:2023-11-14 Accepted:2023-11-15 Published:2024-08-01 Online:2024-01-09
  • Contact: *Department of Physics, Sungkyunkwan University, Su- won 16419, Republic of Korea. E-mail addresses: . sgjung@scnu.ac.kr (S.-G. Jung), **tp8701@skku.edu (T. Park)

Abstract: The high-entropy alloy (HEA) superconductor, Ta1/6Nb2/6Hf1/6Zr1/6Ti1/6 (Ta-Nb-Hf-Zr-Ti), is systematically studied to examine changes in superconducting critical properties, critical temperature (Tc), critical current density (Jc), and upper critical field (Hc2), concerning thermal treatment conditions. Annealing condition affects Jc more significantly than Tc and Hc2, with a large improvement of flux pinning force density (Fp). The Jc of bare sample is reduced to 10 A cm-2 at an applied magnetic field of approximately 1.5 T, whereas the sample annealed at 550 °C for 12 h exhibits Jc > 100 kA cm-2 up to around 4 T. Furthermore, the Vickers hardness (HVIT) of the Ta-Nb-Hf-Zr-Ti HEA superconductor notably increases from ∼384 to 528 HVIT following a 24-h annealing at 500 °C. These results demonstrate that thermal annealing is a powerful process to optimize both the superconducting and mechanical properties of high-entropy alloy superconductors.

Key words: High-entropy alloy superconductor, Ta-Nb-Hf-Zr-Ti, Annealing, Critical current density, Hardness