Single crystal growth and physical properties of Kondo insulator YbB12

YbB12 is the only Yb-based Kondo insulator. We have succeeded for the first time in growing a large single crystal (6 mm empty set x 50 mm) of YbB12 by floating zone method using a newly developed image-furnace with four xenon lamps. The results of the electrical resistivity, Hall effect and magnetic susceptibility measurements indicate that the quality of this crystal is better than that of the best polycrystal ever reported. (C) 1998 Elsevier Science B.V. All rights reserved.