6533b82efe1ef96bd1293bfc

RESEARCH PRODUCT

OH/OD-IR absorption bands in SrxBa1−xNb2O6

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description

Single crystals of Sr x Ba 1−x Nb 2 O 6 (SBN) with congruent composition (x = 0.61) and Sr 0.61 Ba 0.39 Nb 2 O 6 crystals doped with various concentrations of cerium are grown with the Czochralski method. A subsequent doping of the crystals with protons and deuterons is performed either by hydrothermal high temperature treatment or by field supported hydrogen diffusion at elevated temperatures in humid atmosphere. The presence of the protons is revealed by the infrared absorption of the OH stretching vibration. This broad OH absorption band is essentially the same for Sr 0.61 Ba 0.39 Nb 2 O 6 and Sr 0.61 Ba 0.39 Nb 2 O 6 :Ce (0.025 wt% CeO 2 ). It shows a polarization dependence with respect to the c-axis of the tetragonal tungsten bronze structure of Sr x Ba 1−x Nb 2 O 6 , the absorption being stronger for light polarized perpendicular to c than for light polarized parallel to c. The maximum of the OH absorption based is at ν 01,OH = 3496 cm −1 (at room temperature) for light propagating parallel c. At ν 02,OH = 6817 cm −1 the very weak first overtone of the OH stretching vibration can be observed. An analogous absorption band of the fundamental OD stretching vibration is observed at ν 01,OD = 2581 cm −1 . The observed OH and OD vibrational transition wave numbers can be described very well by a Morse-type potential