| Autor: |
I. Kusevic, Emil Babić, Shi Xue Dou, Ž. Marohnić, Đuro Drobac, X.L. Wang |
| Rok vydání: |
2002 |
| Předmět: |
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| Zdroj: |
Solid State Communications. 122:347-350 |
| ISSN: |
0038-1098 |
| DOI: |
10.1016/s0038-1098(02)00120-5 |
| Popis: |
The results of accurate electrical resistivity and ac susceptibility measurements for a well-characterized, single phase MgB2 sample are reported. The onset of electrical resistivity in magnetic fields B less than or equal to I T is thermally activated R exp(-U(T, B)/k(B)T) with U-0(B) = U(T = 0, B) infinity 1/rootB for B greater than or equal to 0.2T. The pinning potential U-0(B less than or equal to I T) is similar to that for YBa2Cu3O7 compound, but the region of flux liquid is quite narrow and the uppercritical field Bc(2) fairly low. High-resolution ac susceptibility measurements show homogeneous superconducting behavior (no Josephson coupled grains) and yield true zerofield critical cur-rent density J(c) similar to (1 - T/T-c)(n) with n approximate to 1.2. The comparison of literature results for J(c) with our ones shows pronounced mass density dependence of J(c) in bulk untextured MgB2 samples. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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