@article{RoshchupkinOrtegaPlotitcynaetal.2016,
  author    = {Roshchupkin, Dmitry and Ortega, Luc and Plotitcyna, Olga and Erko, Alexei and Zizak, Ivo and Vadilonga, Simone and Irzhak, Dmitry and Emelin, Evgenii and Buzanov, Oleg and Leitenberger, Wolfram},
  title     = {Piezoelectric Ca3NbGa3Si2O14 crystal: crystal growth, piezoelectric and acoustic properties},
  series = {Journal of geophysical research : Space physics},
  volume    = {122},
  journal   = {Journal of geophysical research : Space physics},
  publisher = {Springer},
  address   = {New York},
  issn      = {0947-8396},
  doi       = {10.1007/s00339-016-0279-1},
  pages     = {2803 -- 2812},
  year      = {2016},
  abstract  = {Ca3NbGa3Si2O14 (CNGS), a five-component crystal of lanthanum-gallium silicate group, was grown by the Czochralski method. The parameters of the elementary unit cell of the crystal were measured by powder diffraction. The independent piezoelectric strain coefficients d(11) and d(14) were determined by the triple-axis X-ray diffraction in the Bragg and Laue geometries. Excitation and propagation of surface acoustic waves (SAW) were studied by high-resolution X-ray diffraction at BESSY II synchrotron radiation source. The velocity of SAW propagation and power flow angles in the Y-, X-and yxl/+36 degrees-cuts of the CNGS crystal were determined from the analysis of the diffraction spectra. The CNGS crystal was found practically isotropic by its acoustic properties.},
  language  = {en}
}
@article{VadilongaZizakRoshchupkinetal.2017,
  author    = {Vadilonga, Simone and Zizak, Ivo and Roshchupkin, Dmitry and Evgenii, Emelin and Petsiuk, Andrei and Leitenberger, Wolfram and Erko, Alexei},
  title     = {Observation of sagittal X-ray diffraction by surface acoustic waves in Bragg geometry},
  series = {Journal of applied crystallography},
  volume    = {50},
  journal   = {Journal of applied crystallography},
  publisher = {International Union of Crystallography},
  address   = {Chester},
  issn      = {1600-5767},
  doi       = {10.1107/S1600576717002977},
  pages     = {525 -- 530},
  year      = {2017},
  abstract  = {X-ray Bragg diffraction in sagittal geometry on a Y-cut langasite crystal (La3Ga5SiO14) modulated by Lambda = 3 mu m Rayleigh surface acoustic waves was studied at the BESSY II synchrotron radiation facility. Owing to the crystal lattice modulation by the surface acoustic wave diffraction, satellites appear. Their intensity and angular separation depend on the amplitude and wavelength of the ultrasonic superlattice. Experimental results are compared with the corresponding theoretical model that exploits the kinematical diffraction theory. This experiment shows that the propagation of the surface acoustic waves creates a dynamical diffraction grating on the crystal surface, and this can be used for space-time modulation of an X-ray beam.},
  language  = {en}
}