Synthesis, structure, and resistivity properties of K{sub 1{minus}x}Ba{sub x}NbO{sub 3} (0.2{<=}x{<=}0.5) and K{sub 0.5}Sr{sub 0.5}NbO{sub 3}
- Moscow State Univ. (Russian Federation). Dept. of Chemistry
- Moscow State Univ. (Russian Federation). Dept. of Chemistry; and others
The K{sub 1{minus}x}Ba{sub x}NbO{sub 3} (0.2{<=}x{<=}0.5), BaNbO{sub 3} and K{sub 0.5}Sr{sub 0.5}NbO{sub 3} compounds have been synthesized by high-pressure high-temperature technique in a Belt-type apparatus. The synthesis of the K-containing phases carried out in evacuated sealed silica tubes led to the preparation of polyphasic samples. The phases obtained have an ideal perovskite-like structure. The a parameter of Ba-containing compounds increases concomitantly with increasing Ba concentration. Studies of the K-containing phases by X-ray powder diffraction did not reveal any distortion from cubic symmetry. Electron Dispersive Spectroscopy (EDS)analysis confirmed the cation nominal stoichiometry. Resistivity measurements showed semiconducting-like type of conductivity for the K{sub 1{minus}x}Ba{sub x}NbO{sub 3} (0.2{<=} x {<=} 0.5) and K{sub 0.5}Sr{sub 0.5}NbO{sub 3} samples, but the relative increase of {rho} with the decrease of temperature became smaller for the phases with lower Nb valence, and moreover K{sub 0.5}Sr{sub 0.5}NbO{sub 3} exhibited a slight decrease of the resistivity in the 100--4.2 K temperature range. On the contrary, BaNbO{sub 3} after high-pressure treatment showed a metallic-like behavior down to 4.2 K.
- OSTI ID:
- 137042
- Journal Information:
- Materials Research Bulletin, Vol. 30, Issue 11; Other Information: PBD: Nov 1995
- Country of Publication:
- United States
- Language:
- English
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