التفاصيل البيبلوغرافية
| العنوان: |
Structural and physical properties of the II-type superconductor Nb5Si2B. |
| المؤلفون: |
Falkowski, M., Śniadecki, Z., Bednarchuk, T. J., Kowalczyk, A. |
| المصدر: |
Journal of Applied Physics; 6/28/2023, Vol. 133 Issue 24, p1-9, 9p |
| مصطلحات موضوعية: |
SUPERCONDUCTING transitions, SUPERCONDUCTORS, THERMAL conductivity, MAGNETIC flux density, HEAT capacity, SPECIFIC heat, POLYCRYSTALLINE silicon |
| مستخلص: |
In this article, we report on the basic physical properties of a polycrystalline Nb 5 Si 2 B sample, presenting and discussing experimental results of the temperature and field-dependent magnetization M(T, μ 0 H), heat capacity C p (T), electrical resistivity ρ (T), thermoelectric power S(T), and thermal conductivity κ (T) measurements. We also refer to the crystal structure properties of the obtained phase, but primarily we focus on determining the superconducting properties, because based on above experimental data, we deduce on the second-type bulk superconducting transition at T c ≃ 8.2 K. A set of characteristic superconducting state parameters was estimated. Interestingly, although T c gradually and regularly decreases with increasing magnetic field strength, scaling the temperature dependence of the upper critical field μ 0 H c 2 using the Werthamer–Helfand–Hohenberg (WHH) or Ginzburg–Landau (GL) theories does not reflect well on both models. The dimensionless specific heat jump at Δ C p / γ n T c attains ∼ 0.3 , which is significantly smaller than the classical BCS value of Δ C p / γ n T c = 1.43. In addition, the electronic specific heat C e l below T c does not reproduce the isotropic single-gap BCS behavior. Accordingly, these results indicate that Nb 5 Si 2 B is an unconventional BCS superconductor with an anisotropic or multi-valued gap. At T = 300 K, S(T) reaches a negative value of − 5.8 μ V/K and vanishes almost linearly with diminishing temperature, as expected for ordinary metals. On the other hand, from κ (T) data, it turns out that the lattice thermal conductivity dominates over the electronic contribution up to room temperature. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
Complementary Index |
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