MAGNETORESISTANCE AND HALL-EFFECT STUDY OF ELECTRON-DOPED AND HOLE-DOPED CUPRATE SUPERCONDUCTORS

Hall effect measurements on single crystals of the hole-doped systems Y1-xPrxBa2Cu3O7-delta(delta approximate to 0.05) and YBa2Cu3Oy as a fu nction of x and y, respectively, y showed that the Hall conductivity s igma(xy) vs B data in the mixed state could be described by the expres sion sigma(xy) = C-1/B + C2B, where the two terms are associated with motion of the magnetic vortices and the quasi-particles in the vortex cores, respectively, and the parameters C-1 and C-2 are functions of x , y, and T. Magnetoresistance measurements on epitaxial thin films of the electron-doped superconductor Nd1.85Ce0.15CuO4+/-delta with varyin g oxygen content in magnetic fields B parallel to c revealed (a) criti cal scaling of the electrical resistivity data consistent with a vorte x-glass transition for a film with an optimum T-c approximate to 22 K and (b) a characteristic anomaly that develops with increasing field f or T < 2 K for an over-oxygenated film with T-c approximate to 10 K.