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Crystallographic study of component mixture getting CeBa2Cu3Oy

A. STERGIOU1,* , S. YILMAZ1, C. STERGIOU2, B. EGGONOPOULOS –PAPADOPOULOS1

Affiliation

  1. Department of Physics, Laboratory of Applied Physics, Romania
  2. Department of Electrical & Computer Engineering, Romania Aristotle University of Thessaloniki, Greece

Abstract

A powder mixture of BaCO3, Ce2O3 and CuO was prepared, according to the chemical formula CeBa2Cu3Oy. The mixture was annealed progressively, in free atmosphere, at temperatures 860oC to 940oC (with a step of 10oC) for 24 to 72h. Thus, nine samples were obtained and measured by X-Ray powder diffraction, at room temperature, by using a two-cycle diffractometer, with Bragg-Brentano geometry and CuKa radiation. Each sample was characterized with the help of the “Powder Diffraction File” (PDF). The initial crystal structure parameters of crystalline phases were taken from ICSD data base and refined, using the Rietveld’s “Powder Profile Analysis”. The refinement took place progressively, beginning with the powerful phase, at the end of which we added the next one and so on. Three phases were found for first sample: A=BaCeO3 [Pm3m, a=4.3970(2)Å], B=CuO [C2/c, a=4.6902(2)Å, b=3.4163(8)Å, c=5.129(2)Å, β=99.39o(2)] and C=BaCuO2 [Im3m, a=18.288(1)Å]. For the remaining samples the phases A and B were found [for last sample Pm3m, a=4.3595(3)Å and C2/c, a=4.6917(7)Å, b=3.4191(6)Å, c=5.1291(7)Å, β=99.58o(1), respectively]. The C phase appears only in the first sample. The phase A was the main phase and its percentages for the different temperatures are altered between 55.9% and 82.8% w/w, while of B phase between 12.1% and 30.7%. The percentage of C phase is about of 32.05% w/w..

Keywords

Superconductivity, Crystal structure, Phase characterization, Rietveld’s method.

Submitted at: Nov. 14, 2006
Accepted at: June 15, 2007

Citation

A. STERGIOU, S. YILMAZ, C. STERGIOU, B. EGGONOPOULOS –PAPADOPOULOS, Crystallographic study of component mixture getting CeBa2Cu3Oy, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 6, pp. 1779-1784 (2007)