Correlation Between Tc and Crystal Chemical Parameters of Cation Sublattice An+1(Cu)n in Perovskite Layer of High-Tc Cuprate Superconductors

It was found the empirical dependence of T _c of high-temperature superconducting cuprates (HTSC) from the ratio (J) of such parameters as the distances between Cu atoms in CuO₂ plane and the distances from CuO₂ plane to adjacent ones of A cations (A – Ca, Sr, Ba, Y, La, and so on), also from the size and charge of A cations and doping atoms with effect on T _c is proved experimentally. All HTSC phases are divided only on two groups with an intrinsic dependence T _c (J): the phases formed by single CuO₂ plane and by several CuO₂ planes. The closer approximation of that dependence gives the equation of polynomial of third degree.