Anomalous behaviour of noncopper high temperature superconductor Ba1-xKxBiO3

This paper reports on resistivity and I-V measurements that have been carried out on Ba1-xKxBiO3 system in temperature range 2-300 K and magnetic fields up to 8 T. The behavior of resistance below Tc is crucially depended on current value. Dielectric: increase of resistance below Tc at large currents is suppressed by magnetic field and the value of resistance equal to R0 is restored. The temperature dependence of critical magnetic field exhibits positive curvature down to 0.1 Tc and no saturation of Hc2 is observed. The authors suppose that observed effects are the intrinsic properties of single-phase system Ba1-xKxBiO3 and can be explained on the base of model of nonhomogeneous state of dielectric and superconductor coexistence