EFFECTS OF REDOX THERMAL TREATMENTS ON THE TRANSVERSE RESISTANCE PEAKAT THE EDGE OF THE SUPERCONDUCTING TRANSITION IN BI2SR2CACU2O8+X

The growth of the transverse resistivity just above the transition in Bi2Sr2CaCu2O8+x (BSCCO 2212) expitaxial films is studied in the framew ork of the recent fluctuation model proposed by Ioffe, Larkin, Varlamo v and Yu Lu. The effects of different redox thermal treatments on the transverse resistive peak is investigated. The fit of the experimental curves with the theory is good and allows one to estimate the values of some physical parameters included in the theory itself (namely the in-plane Fermi velocity v(F), the carrier lifetime tau and the hopping integral w). It is shown that the oxidizing thermal treatment gives r ise to a strong decrease in the transverse resistance peak just above T(c). Such effect is ascribed to the increase in v(F) due to the growt h of the carrier concentration induced by the oxidizing treatment. Eff ects on the carrier lifetime and the hopping integral are hindered by the large variation of v(F).