SUPERCONDUCTING-STATE THERMODYNAMIC PARAMETERS OF HGBA2CAN-1CUNOY (N=1, 2, 3)

Magnetic measurements have been performed on magnetically aligned, nea rly single-phase samples of HgBa2CuO4+delta, Hg-Ba2CaCu2O6+delta, and HgBa2Ca2Cu3O8+delta. The basic thermodynamic parameters describing the superconducting state, such as the penetration depth and the coherenc e length in the a-b-plane, and the lower and upper critical fields alo ng the c-axis, were determined. A systematic decrease of the penetrati on depth in the a-b-plane, a decrease of Ginzburg-Landau parameter, an d an increase in the thermodynamic critical field with increasing numb er of CuO2 planes in the unit cell are revealed. The values obtained f or the Ginzburg-Landau parameter and the thermodynamic critical field for the Hg-based superconductors are compared with those for YBa2Cu3O7 -delta. The low position of the irreversibility lines for the Hg-based superconductors is attributable to relatively small values of the the rmodynamic critical field.