Synthesis and transport properties ofSrxNbO3(0.75≤x≤0.90)

Abstract

Polycrystalline samples of ${\mathrm{Sr}}_{\mathit{x}}$ ${\mathrm{NbO}}_3$ (0.75≤x≤0.90) have been successfully synthesized by a solid-state reaction technique using TiO as a reducing agent. Powder x-ray-diffraction analysis indicated that the samples with x≥0.80 were single phase of the cubic perovskite structure. Electrical resistivity of each sample exhibited metallic behavior at temperatures below 300 K. For the samples with x<0.90, the magnetic susceptibility was nearly temperature independent (Pauli paramagnetic), while the sample with x=0.90 showed a Curie-Weiss behavior. Since the thermoelectric power coefficient (S) was found to be negative for all the samples in the temperature range between 10 and 300 K, the dominant charge carriers in ${\mathrm{Sr}}_{\mathit{x}}$ ${\mathrm{NbO}}_3$ (0.75≤x≤0.90) were thought to be electrons. On the contrary, the nonlinear temperature dependence of S indicated that electrons in ${\mathrm{Sr}}_{\mathit{x}}$ ${\mathrm{NbO}}_3$ were not simply metallic but rather similar to those in amorphous metals.