CURRENT-VOLTAGE CHARACTERISTICS OF A BI2SR2CA2CU3O8+DELTA CERAMIC SUPERCONDUCTOR

A special contactless technique in combination with the four-probe met hod allowed current-voltage characteristics in a very wide range of el ectric fields E approximately 10(-13) divided-by 10(-1) V/cm to be mea sured on a ring-shaped specimen of the Bi2Sr2Ca2Cu3O8+delta ceramics a t T=77K and different magnetic fields. Experimental data are character ized with an S-like behavior that corresponds qualitatively to the cha racteristic of a single Josephson junction in the presence of thermal fluctuations. At low magnetic fields, a scaling behavior of magnetic f ield dependences of critical currents determined by different voltage levels has been revealed which fails on exceeding an intragrain lower critical field.