FLUX-DENSITY DISTRIBUTION IN YBA2CU3OX THIN-FILMS DETERMINED BY USE OF THE FARADAY-EFFECT IN IRON-GARNET FILMS

The flux penetration and trapping behavior in superconducting YBa2Cu3O(x) films have been observed quantitatively by means of the magnetooptical Faraday effect in iron garnet films with perpendicular magnetization. The mazelike domain pattern of the iron garnet film placed on the superconducting film is affected by the flux in the superconducting film and is observed using a polarizing microscope. Bi- and Ga-substituted YIG films grown by the liquid-phase epitaxy (LPE) method provide suitable characteristics at low temperature for this technique. Flux density profiles are obtained quantitatively for the disk-shaped YBa2Cu3O(x) film. The critical current density is also determined from the profiles.