A new Fz furnace with double ring-shaped halogen lamp heater which had a long heating zone was developed to grow Ba(B1-xAlx)(2)O-4 crystals. The melt in Pt tube set in the new furnace was smoothly fed to the growth interface. As a result, Ba(B1-xAlx)(2)O-4 (x = 0 and 0.05) single crystals, 20 mm in length and 1 mm in diameter, could be grown. (C) 2000 Elsevier Science B.V. All rights reserved.