Composition- and Annealing-Dependent Properties of Ba(Bi,Tl)O3-δ
| Autor: | B. A. Averill, Thomas E. Sutto |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Annealing (metallurgy)
Chemistry Mineralogy Condensed Matter Physics Semimetal Electronic Optical and Magnetic Materials Inorganic Chemistry Crystallography Tetragonal crystal system Electrical resistivity and conductivity Materials Chemistry Ceramics and Composites Diamagnetism Orthorhombic crystal system Physical and Theoretical Chemistry Monoclinic crystal system Solid solution |
| Zdroj: | Journal of Solid State Chemistry. 105:263-270 |
| ISSN: | 0022-4596 |
| DOI: | 10.1006/jssc.1993.1214 |
| Popis: | Solid solutions of BaBiO 3 doped with thallium to give BaBi 1- x Tl x O 3-δ were prepared at 800°C and annealed at 425°C under either argon, air, or oxygen. All samples with x ≤ 0.4 showed an increase in the semiconducting band gap that was accompanied by a decrease in the room temperature diamagnetism, regardless of annealing conditions. Samples with x ≤ 0.4 also exhibited orthorhombic symmetry, rather than monoclinic, as for the parent BaBiO 3 . For compositions centered around BaBi 0.5 Tl 0.5 O 3-δ , however, the resistivity, susceptibility, and structural data were dependent upon the annealing conditions. Insulating behavior and strong diamagnetism (-6.15 × 10 -7 emu/g) were observed for the argon-annealed sample, which had δ = 0.84 and possessed tetragonal symmetry with a = 6.0724 and c = 8.9101 A. The air-annealed sample had a value of δ = 0.46, was a semiconductor or semimetal with a transition to metallic behavior at 73 K, and exhibited moderate room temperature diamagnetism (-3.17 × 10 -7 emu/g) and an orthorhombic unit cell with a = 6.0713, b = 6.1123, and c = 8.5790 A. Oxygen annealing gave a material with δ = 0.0 that was weakly semiconducting and weakly diamagnetic at room temperature (-0.35 × 10 -7 emu/g), and possessed a tetragonal unit cell with a = 6.0778 and c = 8.5418 A. These results are interpreted in terms of the extent and possible ordering of the oxygen vacancies and/or metal atoms. |
| Databáze: | OpenAIRE |
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