Anomalous magnetic field dependence of the thermodynamic transition line in the isotropic superconductor (K,Ba)Bi03

Abstract

Thermodynamic (specific heat, reversible magnetization, tunneling spectroscopy) and transport measurements have been performed on high quality (K,Ba)BiO${}_3$ single crystals. The temperature dependence of the magnetic field $H_{Cp}$ corresponding to the onset of the specific heat anomaly presents a clear positive curvature. $H_{Cp}$ is significantly smaller than the field $H_{\Delta }$ for which the superconducting gap vanishes but is closely related to the irreversibility line deduced from transport data. Moreover, the temperature dependence of the reversible magnetization present a strong deviation from the Ginzburg--Landau theory emphasazing the peculiar nature of the superconducting transition in this material.

4 pages, 4 figures, 28 references

References in corpus (1)

• Upper critical field in {Ba${}_{1-x}$K${}_x$BiO${}_3$}: magnetotransport versus magnetotunneling

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• The magnetization of PrFeAsO${}_{0.60}$F$_{0.12} sueprconductor
• Theory of a Higher Order Phase Transition: Superconducting Transition in BKBO