Hall effect in high-Tc Y1Ba2Cu3O7-δ superconductor

Abstract

We have performed point-by-point and continuous Hall effect experiments as a function of temperature in polycrystalline Y1Ba2Cu3O7-δ. We have shown that the positive Hall constant shows an abrupt increase upon decreasing temperature at a value just above Tc. This temperature corresponds to where the resistance versus temperature data deviates from linearity. At very high fields of 6.8 and 15 T we observe a subsequent decrease in RH. We interpret these data as supportive of a contribution toward the superconductivity mechanism arising from internal excitions or change transfer excitations such that the bound exciton concentration increases near Tc at the expense of positive carries which are reflected in both bound and free holes.