Crystal structure and inelastic neutron scattering in the infinite-layer compounds Sr_1-xNd_xCuO₂

The infinite-layer compounds have rather simple crystal structure and thereby offer an ideal system towards an improved understanding of the phenomenon of high-T c superconductivity. New method for synthesis of IL compounds has been developed. The sets of the samples with rare-earth content of 0.05<x<0.18 were produced. Their crystal structure and oxygen distribution in sublattieies were studied by means of X-ray and neutron powder diffraction. Inelastic neutron scattering has been employed to search for crystalline-electric-field transitions in these compounds. Based on the present results as veil as taken from the current literature, the ratio a/c of the crystal lattice constants is suggested to be an empirical parameter for the existence of superconductivity in the electrondoped infinite-layer system Sr_1-xNd_xCuO₂.