EFFECTS OF CA AND EU SUBSTITUTION FOR SR IN SRXNBO3

We investigated the structural and physical properties of (Sr,M)xNbO3 (M = Ca and Eu) compounds. Polycrystalline samples of Sr0.9-yEuyNbO3 ( 0 less-than-or-equal-to y less-than-or-equal-to 0.9) were synthesized with a solid-state reaction using TiO as the reducing agent. Powder-x- ray-diffraction analysis indicated that the samples with y less-than-o r-equal-to 0.9 were nearly a single phase of the cubic perovskite stru cture. For each of the samples, the electrical resistivity (rho) and t he magnetic susceptibility (chi) exhibited, respectively, metallic and Curie-Weiss behavior at temperatures below 300 K. The valence of the doped Eu ion was found to be in between +2 and +3 according to an x-ra y-photoelectron spectroscopic analysis. Furthermore, nearly single-pha se samples of Sr0.9-zCazNbO3 (0 less-than-or-equal-to z < 0.2) were su ccessfully synthesized with the same preparation technique. For the sa mples with z less-than-or-equal-to 0.2, rho exhibited metallic behavio r at temperatures below 300 K and chi was nearly temperature independe nt, i.e., Pauli paramagnetic.