Complex investigations of the photoinduced changes in YBa2Cu3O x single crystals were performed. As laser sources the low-power He-Ne, He-Cd, He-Se, N2 lasers and YAG:Nd, XeCI pulsed lasers were used. For the investigations the crystalline samples both in super-and semiconducting phases were chosen. A considerably strong dependence of a defectiveness parameter x on the laser power, wavelength and external conditions was observed. The oxygen parameter x shows a tendency to increase for the initially semiconduoting phase and to decrease for superconductors. The most interesting result were obtained using XeCI excimer laser, where corresponding changes ν ere observed only under applied hydrostatic pressure (up to 200 MPa) in oxygen atmosphere. In all the cases the penetration depth of the new induced superconducting phase was within 5.5-6.5 μm.

Synthesis of Pb, Fe and Cd doped Hg-based HgBa 2 Ca 2 Cu 3 O 8+δ (Hg-1223) superconducting ceramics was performed. Hg-free precursor Ba 2 Ca 2 Cu 3 O 8+δ with high chemical homogeneity and reactivity obtained by the sol-gel method was used. The superconducting and impurity phases were determined by means of scanning electron microscopy and microprobe analysis. The results of resistivity and magnetization measurements for different kinds of doped elements were presented.

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Temperature dependences of thermoelectric power S(T) at T > Tc of the Hg-based high temperature superconductors Hg 1−x RxBa 2 Ca 2 Cu 3 O 8+δ (R=Re, Pb) have been analyzed with accounting for strong scattering of charge carriers. Transformation of parameters of a narrow conducting band in the region of the Fermi level was studied. The existence of correlation between the effective bandwidth and the temperature of a superconductive transition Tc is shown.