X-ray photoelectron spectroscopy study and vibration spectra of neodymium doped and undoped Ca0.28Ba0.72Nb2O6 crystal

Calcium barium niobate (Ca0.28Ba0.72Nb2O6, CBN-28) crystallizes with an unfilled tungsten bronze (TB) type structure in the tetragonal system. X-ray photoelectron spectroscopy (XPS) has been performed to explore the effect of Nd-doping on the local electronic environment in the CBN-28 crystal. The content of oxygen vacancies is increased after Nd-doping. The Raman scattering spectrum has been investigated using the back scattering configuration on a CBN-28 crystal and on a crystal with Nd-doping. Comparison of the Raman data obtained for the undoped and Nd-doped CBN-28 crystals reveals slight differences in the shape and position of the Raman peaks. The difference is not readily apparent due to the low Nd3+ content and the intrinsic disorder of the tetragonal tungsten bronze structure.