Crystallization at the center part of a molten zone was carried out using a modified floating zone technique under a 10(-2) g condition in an airplane and under a 1 g condition on the ground using Ba(B0.9Al0.1)(2)O-4 as the source material. A molten zone was formed between a pair of Pt tubes at their upper and lower ends. Molten Ba(B0.9Al0.1)(2)O-4 was crystallized from just the center part of the side surface of the molten zone under the 10(-2) g condition, but from the lower center part of the side surface of the molten zone under the 1 g condition. Crystallization profiles were similar under both conditions. Furthermore, a molten pendant drop of Ba(B0.9Al0.1)(2)O-4 was crystallized on the ground by means of a rod touching at the crystallization temperature using an adequate degree of supercooling. (C) 2002 Elsevier Science B.V. All rights reserved.