High-Tc superconductors from the viewpoint of experiment

Some experimental data on specific heat, critical magnetic field, paramagnetic susceptibility above Tc, the Hall effect, etc., are analyzed for two types of new superconducting materials: lanthanum cuprates and 1-2-3 compounds. The results of this analysis are discussed in terms of applicability of the Fermi-liquid approach to normal and superconducting properties of the new materials, the width of fluctuation region near Tc and dimensionality of the superconductivity are also estimated. The estimated conduction band width and some other microscopic parameters give comparatively broad delocalized electron band (about 0.7 eV). The fluctuation region near Tc appears to be rather narrow though wider than for usual superconductors. The superconductivity is three-dimensional close to Tc, and the layerd structure may become more important far enough from Tc