Direct Observation of Microscopic Inhomogeneities with Energy-Dispersive Diffraction of Synchrotron-Produced X-rays.

Skelton, E F; Drews, A R; Osofsky, M S; Qadri, S B; Hu, J Z; Vanderah, T A; Peng, J L; Greene, R L · Science · 1994

basic_science · Level V

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Abstract

Evidence of structural inhomogeneities in two high-transition-temperature superconductors, YBa(2)Cu(3)O(7-delta) and Nd2-xCexCuO4-y, is presented. When samples were illuminated by highly collimated x-rays produced on a synchrotron wiggler, small changes in the lattice were detected over a spatial scale of 10 micrometers. These changes are interpreted as evidence of variations in the oxygen content in one case and in the cerium content in the other; both affect the superconducting properties. The existence of such structural inhomogeneities brings into question whether exotic experimental results obtained from superconducting materials with high transition temperatures actually reflect intrinsic properties.