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Crystallographic study of NdxBa1-xCuOy (x=0.2, 0.4, 0.6, 0.8) compounds prepared by heating of component mixtures

A. STERGIOU1,* , I. KERASIOTIS1, C. STERGIOU2

Affiliation

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

Abstract

Four powder mixtures of BaCO3, Nd2O3 and CuO was prepared according to the general chemical formula NdxBa1-xCuOy, where x=0.2, 0.4, 0.6, 0.8. The mixtures were heated for 65h in free atmosphere at temperature 930oC. The products were cooled at room temperature and measured by an X-Ray powder diffractometer with Bragg-Brentano geometry and CuKα radiation. Each of the samples was characterized with the help of the “Powder Diffraction File” (PDF). The initial crystal structure parameters of found crystalline phases were taken from ICSD data-base and refined, using the Rietveld’s method. Constant temperature factors for all atoms were used. Four phases were found for whole of the samples: A=NdBa2Cu3O6.6 (Pmmm, a=3.883 to 3.912Å, b=3.843 to 3.889Å, c=11.576 to 11.725Å), B=BaCuO2 (Im3m, a=18.301Å), C=Nd2CuO4 (I4/mmm, a=3.943Å, c=12.173Å), and D=CuO (a=4.794Å, b=3.362Å, c=5.228Å, β=99.79o). The phase A is the main phase and exists in all the samples. In the first sample (x=0.2) the phases A and B were found with percentages 76.8% and 23.2%. In the samples 2 and 3 (x=0.4 and x=0.6) only the A phase exists, while in the fourth one the A, C and D phases exist, with percentages 48.9%, 37.4% and 13.7%..

Keywords

Crystal growth, Crystal structure, Superconductivity, Phase Characterization, Rietveld’s method.

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

Citation

A. STERGIOU, I. KERASIOTIS, C. STERGIOU, Crystallographic study of NdxBa1-xCuOy (x=0.2, 0.4, 0.6, 0.8) compounds prepared by heating of component mixtures, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 6, pp. 1772-1778 (2007)