2-BAND CONDUCTION IN THE NORMAL-STATE OF A SUPERCONDUCTING SM1.85CE0.15CUO4 SINGLE-CRYSTAL

Magnetoresistivity measurements above T(c) (almost-equal-to 14 K) on a superconducting Sm1.85Ce0.15CuO4 single crystal have been performed. In spite of the cerium doping, the low-temperature normal state Hall c oefficient is found to be positive, whereas at high temperature (T > 8 0 K) it becomes negative. The magnetoresistivity has a positive quadra tic field dependence. Both magnetotransport coefficients and resistivi ty are analyzed in terms of a two-band model. We show that the availab le data can be quantitatively described by the competing contributions of electrons and hole-like charge carriers having mobilities mu-1 alm ost-equal-to T2. Holes dominate the low-temperature transport properti es.