William G. Van der Sluys, Alfred P. Sattelberger, et al.
Polyhedron
Metallic-oxygen deficient compounds in ternary systems MOz.sbnd;La2O3CuO with M = Ca, Sr, Ba have been prepared by coprecipitation and subsequent low-temperature solid-state reaction, as well as by high-temperature reaction from the corresponding oxides and carbonates. Substitution of trivalent La by divalent alka-line-earth ions results in sharp drops in resistivity in the 30 - 40 K range, first discovered for the Ba-La-Cu-O system. Room-temperature X-ray powder diffraction shows the presence of a perovskite-like layer-type phase of K2NiF4-type to be responsible for the high Tc super-conductivity. For single-phase samples of La2CuO4 composition, the resistivity drop and especially the onset of the diamagnetic susceptibility are enhanced, and occur near the composition where an orthorhombic-to-tetragonal structural phase transition is detected by X-ray diffraction. © 1987.
William G. Van der Sluys, Alfred P. Sattelberger, et al.
Polyhedron
Heinz Schmid, Hans Biebuyck, et al.
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Ranulfo Allen, John Baglin, et al.
J. Photopolym. Sci. Tech.
A. Gupta, R. Gross, et al.
SPIE Advances in Semiconductors and Superconductors 1990