Oxygen non-stoichiometry and diffusion in RBA2CU3O6+x (R=Y, Gd, Ho) investigated by TG method |
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Authors: | S Chernyaev L Rudnitsky A Mozhaev |
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Institution: | (1) Department of Chemistry, Moscow State University, 119899 Moscow;(2) Institute for Nitrogen Industry, Zemljanoy val 50, 109815 Moscow, Russia |
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Abstract: | By means of thermogravimetry (TG) and chemical analysis equilibrium dependencies of oxygen content in GdBa2Cu3O6+x and HoBa2Cu3O6+x on temperature and
were studied. It is found that at equal temperature and
the oxygen content in RBa2Cu3O6+x increased in order Ho-Y-Gd.On the basis of Fick 2nd law mathematical procedures to determine diffusion coefficients of oxygen from TG data were developed. The oxygen diffusion coefficients in RBa2Cu3O6+x (R=Y, Gd, Ho) were evaluated in a wide temperature (300–900°C) range (at
=0.21 bar). The developed model rather satisfactory decribes oxygen diffusion processes in phases under investigation. It is found that for all studied compounds oxygen diffusion in orthorhombic phase happened faster than in tetragonal one. The values of diffusion coefficients increase in order Ho-Y-Gd with increasing of ionic radius of the rare earth element. |
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Keywords: | GdBa2Cu3O6+x HoBa2Cu3O6+x oxygen non-stoichiometry oxygen diffusion YBa2Cu3O6+x |
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