| Autor: |
Khan, H., Raub, Ch., Lüders, K., Szücs, Z. |
| Zdroj: |
Applied Physics; 1977, Vol. 13 Issue 2, p123-129, 7p |
| Abstrakt: |
For both, the σ-phase and the A-15 phase structure of Nb−Al binary alloys the superconducting properties were investigated in connection with measurements of normal state electronic properties like resistance and NMR-frequency and line width. The A-15 phase shows a transition temperature of T ≈17.5 K. The σ-phase shows only weak transitions at the same temperature which can be explained by A-15 inclusions in a non-superconducting σ-matrix. The Al-Knight shift at room temperature is reduced from 0.162% for pure Al to (0.024±0.002)% and (0.026±0.0025)% for the A-15 and the σ-phase, respectively. The corresponding temperature coefficients differ in sign: positive for the A-15 and negative for the σ-phase; this may have a relation to the different superconducting properties. The NMR line width and the resistance show no different behaviour for the two phases. In general, the electronic properties seems to be less important for the occurance of superconductivity in the Nb−Al system than the lattice structures. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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