Microscopic theory of clean type‐II superconductors in the entire field‐temperature plane

Abstract

Abstract The magnetization curves, the local magnetic field, and the energy gap of clean type‐II superconductors are calculated from Gorkov's theory for all possible values of B, T , and χ by a Ritz variation method. The free energy functional used is derived and discussed in two previous papers. The solutions coincide with all results known so far from approximate theories ( T ≈ T c, , B ≈ H c2 , B«H c2 ). The first principle method yields, for the first time, magnetization curves with a Metastable (S‐shaped) part, thus explaining the jump B o of induction observed at H cl . At not too large values of T and B , the field at the vortex centres increases and the vortex core shrinks both with decreasing B and T . The third form factor, h 20 , is found to change its sign at B/H c2 ≈0.7.