Spin paramagnetism in d-wave superconductors

[摘要] The Ginzburg-Landau equations are derived from the microscopic theory for clean layered superconductors with d(x2-y2) pairing symmetry, including the Pauli paramagnetism effect. The upper critical field H-c2 parallel to the c axis is calculated. A comparison with the experimental data for YBa2Cu3O7-delta suggests that, relative to the orbital effect, the Pauli paramagnetism contribution to H-c2 is significant. The reversible magnetization M in high magnetic fields is also calculated, showing strong temperature dependence of the slope dM/dH, as a consequence of the spin paramagnetism. A simple expression for the high-temperature spin susceptibility is derived, in good agreement with the Knight-shift measurements on YBa2Cu4O8.

[关键词] UPPER CRITICAL-FIELD;YBA2CU3O7-DELTA THIN-FILMS;GINZBURG-LANDAU EQUATIONS;HIGH MAGNETIC-FIELDS;REVERSIBLE MAGNETIZATION;VORTEX STRUCTURE;II SUPERCONDUCTORS;MEGAGAUSS FIELDS;LOW-TEMPERATURE;MODEL