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

Large single crystals of the copper-free Ba1-xKxBiO3 (BKBO) superconductor have been successfully grown using modified method of electrochemical depos ition, For the first time we employed the method of growth where a BaBiO3 s ingle crystal plate was used as a seed. A BKBO layer with(1 0 0) orientatio n and similar to 1 mm thick grown on the substrate was cut off and thereaft er used as a secondary seed. We used a dynamic method, i.e., a crystal bold er with reciprocating motion to homogenize the potassium distribution over the crystal volume. The maximum volume of the as-grown crystals reached sim ilar to 2 cm(3) with the FWHM of the Bragg reflection curves not exceeding 1 degrees. The lattice structure of the Abrikosov vortices as well as the c haracter of defects of the Ba0.6K0.4BiO3 single crystal, caused by the grow th technique, has been studied by small-angle neutron scattering. From SQUI D magnetisation measurements, the growth-induced anisotropy of hysteresis l oops and pinning force of the second-order superconductor are reported. (C) 1999 Elsevier Science B.V. All rights reserved.