Crystal Growth and High-Pressure Effects of Bi-Based Superconducting Whiskers

Ryo Matsumoto; Sayaka Yamamoto; Yoshihiko Takano; Hiromi Tanaka

doi:10.1021/acsomega.1c00880

Crystal Growth and High-Pressure Effects of Bi-Based Superconducting Whiskers

ACS Omega. 2021 Apr 23;6(18):12179-12186. doi: 10.1021/acsomega.1c00880. eCollection 2021 May 11.

Authors

Ryo Matsumoto¹, Sayaka Yamamoto^{2

3}, Yoshihiko Takano^{2

3}, Hiromi Tanaka⁴

Affiliations

¹ International Center for Young Scientists (ICYS), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
² International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
³ University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan.
⁴ National Institute of Technology, Yonago College, 4448 Hikona, Yonago, Tottori 683-8502, Japan.

Abstract

Three growth methods were tested for producing high-transition temperature superconducting Bi₂Sr₂Ca _n-1Cu _n O_2n+4+δ whiskers, employing different ways to focus a compressive stress and size effect of the precursors. First, thermographic imaging was used to investigate thermal stress from temperature distribution in the precursors during growth annealing. To enhance thermal stress in the precursors, a thermal cycling method and a Ag-paste coating method were proposed and found to significantly accelerate the whisker growth. The use of pulverized precursors also promoted whisker growth, possibly due to contribution from the vapor-liquid-solid growth mechanism. The obtained whiskers revealed the typical composition, diffraction patterns, and superconducting properties of the Bi-2212 phase. The proposed methods were able to stably produce longer whiskers compared to the conventional method. Using the obtained whiskers, electrical transport measurements under high pressure were successfully performed up to around 50 GPa.