Ginzburg–Landau theory for two-band s-wave superconductors: application to non-magnetic borocarbides LuNi2B2C, YNi2B2C and magnesium diboride MgB2
✍ Scribed by I.N. Askerzade
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 204 KB
- Volume
- 397
- Category
- Article
- ISSN
- 0921-4534
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✦ Synopsis
Temperature dependence of the upper critical field H c2 ðT Þ, lower critical field H c1 ðT Þ and thermodynamic magnetic field H cm ðT Þ are studied in the vicinity of T c by using a two-band Ginzburg-Landau (G-L) theory. The results are shown to be in a good agreement with experimental data for the superconducting magnesium diboride, MgB 2 , and nonmagnetic borocarbides LuNi 2 B 2 C, YNi 2 B 2 C. In addition, two-band G-L theory was applied for the calculation of specific heat jump, which is smaller than in single-band G-L theory. Peculiarities of Little-Parks effect in two-band G-L theory are studied also. It is shown that quantization of the magnetic flux and relation between surface magnetic field H c3 ðT Þ and upper critical field H c2 ðT Þ are the same as in single-band G-L theory.