MAGNETIC-FIELD INVERSION AND VORTEX CHAINS IN ANISOTROPIC SUPERCONDUCTORS

The magnetic structure of vortices in superconductors with uniaxial anisotropy has been studied. The magnetic field inversion is predicted. There are directions associated with the crystal anisotropy axis where the longitudinal magnetic field is directed opposite to the total magnetic flux in the vortex. As a result, the energy of pair vortex interaction becomes negative and vortices attract each other. They form chains oriented along the symmetry axis. The mutual attraction of the vortices lowers the threshold field of chain creation as opposed to the lower critical field for an isolated vortex. Numerical calculations are made of longitudional field component, equilibrium vortex orientation, separation between the vortices in chains and threshold field of chain creation for superconducting systems Y-Ba-Cu-O and Bi-Sr-Ca-Cu-0. © 1990, Elsevier Science Publishers B.V. (North-Holland). All rights reserved.