Raman spectrum in monoclinic bivo4

Abstract

A boule of BiVO4single crystal was grown by Czochralski technique and annealed for 24 hours at 500°C. The Laue and conoscopic image techniques were used to determine the crystallographic axes of BiVO4 single crystal. The Raman spectrum of c(bb)c geometry of monoclinic BiVO4 was obtained and the Ag symmetry mode appearing at 56 cm-1 at room temperature was softened as the temperature approached to the ferroelastic-paraelastic phase trasition point(255°C). The disappearing of soft Ag mode at phase transition temperature indicates that it is closely related to the ferroelastic strain which controlles the phase transition, i.e., ferroelastic-paraelastic phase transition in BivO4. © 1985 The Japan Society of Applied Physics.