Specific heat in the mixed state of superconducting YBa2Cu3O7-x

It is shown that the observed magnetic-field dependence of the specific-heat anomaly near the superconducting transition temperature Tc of YBa2Cu3O7-x can be understood quantitatively by the Ginzburg-Landau theory of anisotropic type-II superconductors. It is shown, in the London limit, that the change in specific heat by the application of magnetic field Ba(∼1T) is approximately linear in (Ba/Tc)[t/(1-t)] for temperatures slightly below Tc, where t=T/Tc. It is also predicted that the slope of this linear behavior for Ba perpendicular c axis should be (mc/mab)1/2 times lower than that for Ba parallel c axis. Here, mc and mab are the components of the effective-mass tensor parallel and perpendicular to the c axis, respectively