Unrevealed aspects of the photoinduced phase transition are discussed with a special emphasis placed on domains and domain boundaries. The CN− vibration spectroscopy, which is sensitive to the phase changes and boundaries, is applied to photomagnetic phase transition material, RbMn[Fe(CN)6]. From time-resolved IR measurements for photoinduced low temperature to high temperature phase transition, the transient appearance of the boundaries as well as the new phase within 1 ps is observed. The growth processes of the low temperature phase and boundaries during UV irradiation on the sample in high temperature phase are investigated by Raman spectroscopy at room temperature. The result suggests that the new phase appears preferably in the fresh area and a lot of unpaired fragments of high temperature phase are left behind after a prolonged irradiation.
Typical distribution of two phases and boundaries in hexacyanoferrate during photoinduced phase transition (simulation). Blue: initial phase; red: new phase; green: boundary.