2002/12/31 by L. M. Volkova, S. A. Polyshchuk, S. A. Magarill +1
Physics and Astronomy · #cond-mat.supr-con #cond-mat.mtrl-sci
published as J. Supercond. V16, N6, 937-939 (2003) · 4 pages, 2 figures
arxiv created 2004/02/12 · arxiv updated 2009/11/30
The crystal chemical concept of arrangement and function of layered superconducting materials is supposed. The concept is based on results of our investigation of crystal chemistry of high-temperature superconductors (HTSC) cuprates, diborides AB2 and borocarbides of nickel RNi2B2C. According to these results: (1) the main role in appearance of superconductivity played by the structural fragments - sandwiches A2(CuO2) in HTSC cuprates, A2(B2) in diborides and RB(Ni) in nickel borocarbides but not the separate planes of CuO2, B2 or Ni; (2) correlations between Tc and crystal chemical parameters of these sandwiches have similar character in all three classes of compounds, despite of distinction of a nature of their superconductivity. The central idea of the concept consists in following: in contrast to metallic conduction, for which it is enough to provide only concentration and mobility of charge carriers, for occurrence of a superconductivity it is necessary to create in addition a space (channels) for stream of charge carriers, compression of stream of carriers and focusing to direction on path of motion