THERMODYNAMIC FLUCTUATIONS OF THE ORDER PARAMETER IN TYPE II SUPERCONDUCTORS NEAR THE UPPER CRITICAL FIELD H SUB C2.
CORNELL UNIV ITHACA N Y LAB OF ATOMIC AND SOLID STATE PHYSICS
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An investigation was made of the mean square deviation of the order parameter from its equilibrium for Type II Superconductors, assuming that the Gibbs free energy is given by a Ginzburg-Landau type functional. It turns out, that the equilibrium function, which is already varying with position because of the penetrating magnetic flux, resists distortion much less than the constant order parameter in type I superconductors. Therefore, the mean square deviation becomes equal in magnitude to the square of the equilibrium order parameter in the magnetic field range H sub c2-BH sub c2 approx. 0.0001 to 0.00001. This means, that the range of magnetic fields, in which Ginzburg-Landau type descriptions should fail and a singular behavior might show up seems not entirely out of reach of present experimental techniques in contrast to the situation in type I superconductors. Author
- Solid State Physics