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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/3039

Title: Influence of calcium substitution on the formation and thermal stability of the YBa2Cr4O8 superconductor
Authors: VAN BAEL, Marlies
KAREIVA, Aivaras
VANHOYLAND, Geert
MULLENS, Jules
FRANCO, Dirk
YPERMAN, Jan
VAN POUCKE, Lucien
Issue Date: 1999
Publisher: ELSEVIER SCIENCE BV
Citation: THERMOCHIMICA ACTA, 340-341. p. 407-416
Abstract: In order to study the influence of calcium substitution on the thermal stability and phase composition of the YBa2Cu4O8 (Y-124) superconductor, precursor powders with composition Y:Ca:Ba:Cu = 1 - x : x : 2 : 4 (x = 0.0-0.1) are prepared using an acetate-tartrate based sol-gel method, The phase composition of the products formed after different stages of heat treatment at 800 degrees C and under 1 atm oxygen pressure is examined by X-ray powder diffraction (XRD) and thermogravimetric analysis (TGA). We found that in the first stage of the heat treatment, among stable mixed oxides and carbonate, mainly Y2Ba4Cu7Oy (Y-247) and CuO are formed. Upon further heating Y-247 can react with CuO to form Y-124, but can also decompose into Y-124 and YBa2Cu3O7 - y (Y-123). The formation of Y-123 is favoured by an increasing amount of calcium substitution. We also demonstrate that the TGA technique makes it possible to detect and distinguish between the presence of the Y-123, Y-124 and Y-247 when they are simultaneously present in a sample, while this is less obvious using only XRD. (C) 1999 Elsevier Science B.V, All rights reserved.
Notes: Limburgs Univ Ctr, Lab Inorgan & Phys Chem, IMO, B-3590 Diepenbeek, Belgium. Vilnius State Univ, Dept Gen & Inorgan Chem, LT-2006 Vilnius, Lithuania.Mullens, J, Limburgs Univ Ctr, Lab Inorgan & Phys Chem, IMO, Univ Campus, B-3590 Diepenbeek, Belgium.
URI: http://hdl.handle.net/1942/3039
DOI: 10.1016/S0040-6031(99)00285-3
ISI #: 000084236400039
ISSN: 0040-6031
Type: Journal Contribution
Validation: ecoom, 2000
Appears in Collections: Research publications

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