In the communication a significant enhancement of two-beam gain coefficient
reached in modified Sn2P2S6 photorefractive (PR) crystals is reported. The
se crystals were obtained using the vapor-transport technique with the modi
fications including alternate transport agent. The comparative studies of t
he optical and PR parameters of the nominally pure and modified samples wer
e carried out. (C) 2001 Elsevier Science B.V. All rights reserved.