Flux Penetration in an Anisotropic Type-II Superconductor

Calculations are presented for the magnetic induction B and the free energy of an anisotropic type-II superconductor near its upper critical field Hc2. It is shown that this field is not necessarily parallel to the externally applied magnetic field H, its direction depending on the direction of H relative to the principal axes of the Ginsburg effective-mass tensor. These results suggest that torque measurements, made on geometrically symmetrical samples, should be useful in determining the upper critical field Hc2 as well as the components of the effective-mass tensor.