R. Puzniak et al., SUPERCONDUCTING-STATE THERMODYNAMIC PARAMETERS AND ANISOTROPY OF HGBA2CAN-1CUNOY BY REVERSIBLE MAGNETIZATION MEASUREMENTS, Physical review. B, Condensed matter, 52(5), 1995, pp. 3756-3764
Measurements of the reversible magnetization in magnetic fields parall
el and perpendicular to the c axis have been performed on magnetically
aligned nearly-single-phase crystalline HgBa2Can-1CunOy (n = 1, 2, an
d 3) samples. The basic thermodynamic parameters describing the superc
onducting state, such as the penetration depth, the coherence length,
the lower and upper critical fields, and their anisotropy, were determ
ined. The anisotropy of HgBa2Can-1CunOy was found to increase as the n
umber of the copper oxide layers in the unit-cell increases, although
the magnitude of the anisotropy is rather small. Relatively smaller va
lues of the thermodynamic critical field, in comparison with that of Y
Ba2Cu3O7-delta, can cause the lower position of the irreversibility li
nes determined for the Hg-based superconductors.