Channeling study of high-Tc superconducting single crystal sublattices

Backscattering of H, 4He, 3He ions, X-ray radiation and the nuclear reactions 16O(4He, 4He)16O, 18O(p, α)15N, 16O(3He, 4He)15O, 7Li(p, α)4He, etc., in combination with orientation effects have been used to investigate the structure and properties of the single crystals Nd2-xCexCuO4 (T'-phase) and La2-xSrxCuO4 (T-phase). The possibility of a selective study of cation and anion sublattices, as well as of oxygen O1, O2 positions is demonstrated. The dependence of the La2-xSrxCuO4 structural perfection on the Sr content is established. The location of Li and B is determined. Studies were made of the diffusion mobility and adsorption properties of 18O in the YBa2Cu3O7-y ceramics. The influence of crystal irradiation with H and 4He ions on the shapes of the angular dependences of the yields of nuclear reactions was studied. The effect of interest has been observed for the α-yield of the 16O(4He, 4He)16O reaction after 4He ion irradiation of Nd2-xCexCuO4, namely, the dip with χmin(O)≅0.18 transforms to a peak with χmax(O)≅1.5; the χmin(Nd) value changes in this case from 0.024 to 0.19. (orig.)