The position effects of a mirror-lamp (M-L) system on the growth of a rutile crystal by using the infrared convergent-heating floating zone (IR-FZ) method was systematically investigated. Compared with the conventional IR-FZ method, the molten zone for the M-L system was stabilized at a distant position and a large rutile crystal could be grown. However, the roughness of the interface shapes between the feed and molten zones increased at the more distant position of the M-L system. The slower rotation rate of the feed was found to be effective for smoothing the rough feed-side interface. The results of this study showed that the position of the M-L system and rotation of the feed are key factors for the stable growth of a single rutile crystal with a large diameter by using the IR-FZ method. (C) 2018 Published by Elsevier B.V.