A series of chromium-containing solid solutions CaCu3Ti4 – 4хСr4хO12 – ? (sp. gr. Im3) were obtained by the solid-phase synthesis method. The unit cell parameter of the solid solutions changed insignificantly from 7.3897 (х = 0.02) to 7.3866 ? (х = 0.06). Copper oxide was determined in the intergranular space in all samples. The samples were characterized by a low-porosity grain microstructure; with an increase in the chromium content in the samples from x = 0.01 to 0.06, the maximum longitudinal crystallite size, according to the scanning electron microscopy data, decreased from 16 to 10 ?m. Spectral studies of the charge state of chromium-doped titanium calcium copper CaCu3Ti4O12 cations were carried out using X-ray spectroscopy (XPS and NEXAFS). According to NEXAFS and XPS spectroscopy data, titanium cations have a charge state of +(4 – ?) in solid solutions of calcium-copper oxides, copper and calcium atoms have a charge state of +2, and doped chromium cations have a charge state of +3.
Sergey V. Nekipelov – Candidate of Physical and Mathematical Sciences, head of the Laboratory of Experimental Physics, Institute of Physics and Mathematics of the Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia
Boris A. Makeev – Candidate of Geological-Mineralogical Sciences, researcher, Laboratory of Mineralogy, Institute of Geology FRC Komi SC UB RAS, Syktyvkar, Russia
Anna V. Fedorova – Candidate of Chemical Sciences, Associate Professor, Department of Inorganic Chemistry, Saint Petersburg State University, Saint Petersburg, Russia
Nadezhda A. Zhuk – Candidate of Chemical Sciences, Associate Professor, senior researcher, Laboratory of Ceramic Materials Science, Syktyvkar State University, Syktyvkar, Russia
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