NONOHMIC RESPONSE UNDER LOW MAGNETIC-FIELDS IN BSCCO

The influence of low magnetic fields parallel to the c-axis on the vor tex-antivortex (v-a) distribution in one BSCCO crystal and in one orie nted film is studied by examining the changes of the non-ohmic respons e near the superconducting transition. The obtained results confirm th e non-external magnetic origin of a v-a configuration and are interpre ted by a losening and a depairing of the v-a couples in a way similar to that produced by the temperature. Phenomenological dependences of t he two effects are proposed.