| Autor: |
Kromer, F., Oeschler, N., Tayama, T., Tenya, K., Cichorek, T., Lang, M., Steglich, F., Kim, J., Stewart, G. |
| Zdroj: |
Journal of Low Temperature Physics; Feb2002, Vol. 126 Issue 3/4, p815-833, 19p |
| Abstrakt: |
We report on recent magnetic field studies on U 1−xThxBe 13 with x≤ 0.1. These new results are related to previous data published by Kromer et al. [F. Kromer et al., Phys. Rev. B 62, 12477 (2000)]. The new magnetization measurements confirm the existence of an anomaly found earlier through calorimetric and dilatometric measurements at T L c for x c1≈ 0.019. In the critical concentration range x c1 c2≈ 0.0455, the critical-field curves for the mean field type of phase transition that occur at T c1 and T c2 (at zero field) appear to merge as T→ 0. This interesting fact which has been inferred already from the previous measurements could be confirmed for a sample with x= 0.038. The normal state for Th concentrations x≈xc 2 is rather unusual: A negative normal-state contribution, αn, is observed in the thermal expansion coefficient as well as the occurrence of a positive peak when superconductivity is suppressed by a magnetic field. Both effects are studied in detail and a comparison to specific heat results is given. Finally, we have investigated the non-linear contribution to the magnetization, χ (3), of UBe 13 and U 0.9Th 0.1Be 13. In contradiction to suggestions made previously by Aliev et al. [Aliev et al., Europhys. Lett. 32, 765 (1995)] for x=0.1, χ (3) remains negative down to T≈ 100 mK, the lowest temperature investigated. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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