Specific heat of high temperature superconductors: Role of $\mid \psi   \mid^{4}$ term in Ginzburg--Landau free energy
  We have derived the expression for the specific heat by using Ginzburg-Landau (GL) theory by taking $\mid \psi \mid^{4}$ into account in the Hartree approximation. Without this term, the specific heat diverges at $T=T_{c}(B)$. It is also shown that width and shape of the transition depends on the value of $\alpha$ and $\beta$, the coefficients in the GL free energy. 
Bikash. Ch. Gupta and K. K. Nanda