HALL-COEFFICIENTS OF ND2-XCEXCUO4 THIN-FILMS

Cerium concentration dependence of Hall coefficient in Nd2-xCexCuO4 thin films has been examined. It is confirmed that the Hall coefficient R(H) at Ce concentrations of x approximately 0.15 where the superconducting critical temperature T(c) becomes maximum is negative. It is found, however, that R(H) changes rapidly for positive behavior with a small increase of Ce concentration, and finally becomes completely positive in the whole temperature range below 300 K at Ce concentration values where the system is still superconductive. A confusion in the sign of the carriers in bulk samples is thought to originate from a Ce distribution nonuniformity in these samples.