High-temperature Raman spectra of KDP:Ni crystal

Abstract

High-temperature Raman scattering measurements of KDP doped with Ni (1% weight) were performed over the spectral range 50–1200cm−1. The X-ray powder diffraction patterns taken at room temperature and analyzed by Rietveld refinement showed that doped samples of KDP:Ni have the same tetragonal structure of a pure KDP crystal, but with a contraction of the crystalline cell. The behavior of the high-temperature Raman spectra indicate that two phase transitions occur, one at 413K and another one at 443K. These phase transitions occur at temperatures below the thermal dehydratation point, 488K. DTA and TGA measurements reveals that KDP:Ni and pure KDP have the same thermal dehydratation temperature.