STUDY OF MGO-SUBSTITUTION IN LINBO3 SINGLE-CRYSTALS BY USING MICRO-PROBE RAMAN-SPECTROSCOPY

Micro-Probe Raman Spectroscopy (MPRS) was used to measure the MgO-subs titution effect in MgO-doped, congruent LiNbO3 (MgO = 0 to 10 mole% in 2.5 mole% step) single crystals, As the content of MgO was increased, the overall intensities of the vibrational modes increased. As expect ed from previous electrical measurements, the internal vibrational mod es that were related to the O-Nb-O vibration changed the most. Especia lly, the modes that were located at 273 cm(-1) and 324 cm(-1) almost d isappeared when 10% of MgO was doped in the LiNbO3 host material. Thes e two peaks correspond to the internal nu(3) and nu(4) vibrations in t he NbO6 octahedron. This implies that the Nb sites in pure LiNbO3 have the largest change when MgO is incorporated into pure LiNbO3.