PHASE OF THE COMPOSITION CaBaLaCu2FeO7.5: SYNTHESIS, STRUCTURE, MГ–SSBAUER SPECTRA
V. G. Bekeshev, Y. N. Kil'yanov, R. A. Stukan
Keywords: high-temperature superconductors, systems 123, 57Fe M?ssbauer spectroscopy, powder X-ray diffraction analysis
Pages: 387-390
Abstract
The phase of the composition CaBaLaCu2FeO7.5 is synthesized from the previously obtained CaCuO2, La2Cu2O5, and BaFeO2 double oxides enriched up to 14.7% in 57Fe. The phase has the orthorhombic crystal system with the unit cell parameters as follows: a = 0.3882(3) nm, b = 0.3911(3) nm, c = 1.1823(8) nm. Based on the Mössbauer spectra analysis, the conclusion is drawn that iron atoms occupy only Cu(1) sites in the lattice, while more than 90% of them are in the Fe4+ valence state (80% of these atoms have the tetragonal pyramidal coordination).
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