Specific heat and critical fluctuations in anisotropic high-Tc oxide superconductors

The specific heat due to the fluctuation of the order parameter is evaluated from the Modified Ginzburg-Landau free energy functional for high Tc superconductors. The Ginzburg criterion was estimated from the Gaussian fluctuation contribution to the specific heat. The obtained criterion implies that the breakdown of the Modified Ginzburg-Landau mean-field theory takes place in a rather wide temperature range for the new superconductors. Comparison with the available experimental data is presented. (author). 23 refs