A new method for growing Ba1−xKxBiO3 single crystals and investigation of their properties

Abstract Large single crystals of the copper-free Ba 1− x K x BiO 3 (BKBO) superconductor have been successfully grown using modified method of electrochemical deposition. For the first time we employed the method of growth where a BaBiO 3 single crystal plate was used as a seed. A BKBO layer with (1 0 0) orientation and ∼1 mm thick grown on the substrate was cut off and thereafter used as a secondary seed. We used a dynamic method, i.e., a crystal holder with reciprocating motion to homogenize the potassium distribution over the crystal volume. The maximum volume of the as-grown crystals reached ∼2 cm 3 with the FWHM of the Bragg reflection curves not exceeding 1°. The lattice structure of the Abrikosov vortices as well as the character of defects of the Ba 0.6 K 0.4 BiO 3 single crystal, caused by the growth technique, has been studied by small-angle neutron scattering. From SQUID magnetisation measurements, the growth-induced anisotropy of hysteresis loops and pinning force of the second-order superconductor are reported.