The chemical composition of uranium-containing phase particles in U-doped Y-Ba-Cu-O melt processed superconductor

The microstructure of melt processed uranium doped Y-Ba-Cu-O superconductors (YBCO) contains Y2BaCuO5 phase (Y-211) and uranium phase particles within a textured superconducting YBa2Cu3O7 (Y-123) phase matrix. The size of these uranium phase particles lies typically in the range of 0.3-0.5 mum in the YBCO system. In this paper the chemical composition of the uranium phase particles has been investigated using electron probe microscopy. Various samples with initial chemical composition close to the measured value have been synthesised and used to identify a stable uranium-containing phase present in melt processed U-doped YBCO. The magnetic properties of the uranium phase compounds have been measured over a wide temperature range to investigate their potential role in increasing J(c) in bulk melt processed samples. (C) 2003 Elsevier B.V. All rights reserved.