Structure and transport properties of superconductive Nd2CuO4−xFx

Abstract We report the TEM observation and Hall measurements of polycrystalline superconductive Nd 2 CuO 4−x F x samples. For the Nd 2 CuO 3.8 F 0.2 sample with T c , on =27 K and T c , zero =20 K , a TEM observation shows no evidences for the existence of any types of structural modulations. For the samples with 0.1≤x≤0.3, the Hall coefficient (R H ) is found to be negative in the temperature range between 30 and 275 K. Moreover, the temperature dependence of R H seems to be similar to that for an n-type superconductor, Nd 1.85 Ce 0.15 CuO 4 .