Superconducting properties of the family of mercurocuprates and role of layered structure

The various phases of the homologous series HgBa{sub 2}Ca{sub n{minus}1}Cu{sub n}O{sub 2n+2+{delta}} were synthesized earlier using the program-controlled high pressure chamber. The authors observed that dependence of T{sub c}(a), where a is the in-plane lattice constant (and consequently oxygen content {delta}) have a typical bell-shaped character. T{sub c} versus lattice constant has a similar bell-shaped curve for several values of n, with the maximum T{sub c} value measured for n = 3. They have analyzed this dependence (and of the formal copper valence) for different members of mercurocuprate family in terms of the phenomenological model of layered superconductors taking into account possible charge redistribution. The experimentally observed nonmonotonic bell-shaped dependence T{sub c}(n) was consistent with the model.