Answers are grounded in this paper and cite their sources.
A two-step resistive transition, one beginning at 240 K and the other at 90 K, has been observed in Y-Ba-Cu-O compounds. The superconductivity, possibly in granular form, at both temperatures has been verified by means of the rf-to-dc conversion associated with the ac Josephson effect.
No takes yet. Share an insight, caveat, or question.
Chen et al. (1987) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: