Superconducting-Normal Phase Transition in (Ba1−xKx)BiO3, x=0.40, 0.47

B. F. Woodfield; D. A. Wright; R. A. Fisher; N. E. Phillips; H. Y. Tang

doi:10.1103/PhysRevLett.83.4622

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Superconducting-Normal Phase Transition in (Ba1−xKx)BiO3, x=0.40, 0.47

B. F. Woodfield, D. A. Wright, R. A. Fisher, N. E. Phillips, H. Y. Tang

DOI 10.1103/PhysRevLett.83.4622 · Physical Review Letters

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Abstract

Specific-heat measurements on (Ba1−xKx)BiO3, x=0.40 and 0.47, 0.7≤T≤35K, 0≤H≤9T, have determined the coefficient (γ) of the normal-state conduction electron specific heat, and shown well-defined specific-heat anomalies at Tc that are consistent with the value of γ and BCS expressions. These results contradict the suggestion in a recent Letter that γ is several orders of magnitude greater than these experimental values and that the absence of a correspondingly large specific-heat anomaly constitutes evidence that the transition is an Ehrenfest fourth-order transition.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Ba0.60K0.40BiO3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	30	Pressure not reported	unknown
Ba0.53K0.47BiO3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	21	Pressure not reported	unknown