CURRENT-VOLTAGE CHARACTERISTICS OF BI2SR2CA1CU2O8 SINGLE-CRYSTALS - POSSIBLE PLASTIC-DEFORMATIONS OF THE VORTEX LATTICE

The J-E curves (JEC) for Bi2+xSr2+yCa1+zCu2O8+t single crystals have b een extracted from results of VSM magnetic measurements. The obtained data show the existence of two temperature regions with a transition t emperature T between 15 and 20 K being dependent on the voltage crite ria. Below T, JECs are described quite well by a power-like law E/E(c )=(J/J(c))n with n is-proportional-to 1/T. For high magnetic fields it is found that 1/n is-proportional-to B. A model considering the ''pan cake'' vortex-antivortex pair excitation provides good consistency wit h the experimental data.