Structural and electronic instabilities in AgMo6Se8
| Autor: | R.S. McLean, W.R. McKinnon, David W. Johnson |
|---|---|
| Rok vydání: | 1989 |
| Předmět: |
Superconductivity
Condensed matter physics Chemistry Chalcogenide Fermi level Condensed Matter Physics Magnetic susceptibility Semimetal Thermal expansion Electronic Optical and Magnetic Materials Inorganic Chemistry symbols.namesake chemistry.chemical_compound Materials Chemistry Ceramics and Composites symbols Density of states Physical and Theoretical Chemistry Solid solution |
| Zdroj: | Journal of Solid State Chemistry. 82:35-42 |
| ISSN: | 0022-4596 |
| DOI: | 10.1016/0022-4596(89)90219-3 |
| Popis: | The structural parameters, superconducting critical temperatures, and magnetic susceptibilities of the solid solution AgMo 6 S 8− x Se x are reported. The behavior of the physical properties across the solid solution are similar to those observed for other ternary molybdenum chalcogenide solid solutions, except for the end member, AgMo 6 Se 8 , which has an anomalously low superconducting critical temperature relative to those observed in the solid solution. A discontinuity in the magnetic susceptibility of AgMo 6 Se 8 was observed at 110 K. The decrease in the Pauli susceptibility at this temperature reflects a reduction in the density of states at the Fermi level which leads to the low T c observed for this compound. Since structural distortions are a likely cause of such anomalies, the temperature dependence of the lattice parameters of this material was investigated. A discontinuity in thermal expansion was discovered at the same temperature observed for the discontinuity in the magnetic susceptibility. This suggests that a structural distortion may be responsible for the decrease in the density of states, although our X-ray study did not show any splitting of the Bragg reflections. The presence of a structural distortion, however, also affords an explanation for the positive pressure dependence of the superconducting critical temperature of this material previously reported. The application of pressure will stabilize the high-temperature structure, thereby increasing the density of states. The increased density of states results in an increased superconducting critical temperature. |
| Databáze: | OpenAIRE |
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