Dependence of superconductivity in on quenching conditions
- Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., Stony Brook, NY (United States)
- Brookhaven National Lab. (BNL), Upton, NY (United States)
Topological superconductivity, implying gapless protected surface states, has recently been proposed to exist in the compound CuxBi₂Se₃. Unfortunately, low diamagnetic shielding fractions and considerable inhomogeneity have been reported in this compound. In an attempt to understand and improve on the finite superconducting volume fractions, we have investigated the effects of various growth and post-annealing conditions. With a melt-growth (MG) method, diamagnetic shielding fractions of up to 56% in Cu₀̣₃Bi₂Se₃ have been obtained, the highest value reported for this method. We investigate the efficacy of various quenching and annealing conditions, finding that quenching from temperatures above 560°C is essential for superconductivity, whereas quenching from lower temperatures or not quenching at all is detrimental. A modified floating zone (FZ) method yielded large single crystals but little superconductivity. Even after annealing and quenching, FZ-grown samples had much less chance of being superconducting than MG-grown samples. Thus, from the low shielding fractions in FZ-grown samples and the quenching dependence, we suggest that a metastable secondary phase having a small volume fraction in most of the samples may be responsible for the superconductivity.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Emergent Superconductivity (CES)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0012704; SC00112704
- OSTI ID:
- 1193223
- Alternate ID(s):
- OSTI ID: 1178485
- Report Number(s):
- BNL-108107-2015-JA; PRBMDO; R&D Project: PO010; KC0201060
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 91, Issue 14; ISSN 1098-0121
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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