Flux creep in a polycrystalline Ba0.6K0.4BiO3 superconductor

M. E. McHenry; M. P. Maley; G. H. Kwei; J. D. Thompson

doi:10.1103/PhysRevB.39.7339

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Flux creep in a polycrystalline Ba0.6K0.4BiO3 superconductor

M. E. McHenry, M. P. Maley, G. H. Kwei, J. D. Thompson

DOI 10.1103/PhysRevB.39.7339 · Physical Review B

T1

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Abstract

Magnetization curves have been measured as a function of temperature for a polycrystalline sample of Ba0.6K0.4BiO3. These measurements reveal significant reversibility at modest fields for all temperatures studied. The irreversibility line (H*,T*) is determined for this material and shows that H* is less than 0.8 T at all temperatures. The logarithmic magnetic relaxation rate A=dM/d ln(t) has been studied for this material, as a function of both field and temperature. Analysis using the flux-creep model reveals the average pinning energy U0 to be 0.08±0.02 eV. This extremely small pinning energy is used to explain the small critical current, its strong dependence on field, and the significantly reversible behavior in this material.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Ba0.6K0.4BiO3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	29	Pressure not reported	onset
Ba0.6K0.4BiO3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	26	Pressure not reported	midpoint
Ba1-xKxBiO3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
Ba(Pb,Bi)O3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
YBa2Cu3O7-x Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown