S Patnaik et al 2001 Supercond. Sci. Technol. 14 315 doi:10.1088/0953-2048/14/6/304
Electronic anisotropy, magnetic field-temperature phase diagram and their dependence on resistivity in c-axis oriented MgB2 thin films
S Patnaik1, L D Cooley1, A Gurevich1, A A Polyanskii1, J Jiang1, X Y Cai1, A A Squitieri1, M T Naus1, M K Lee2, J H Choi2, L Belenky2, S D Bu2, J Letteri3, X Song1,2, D G Schlom3, S E Babcock1,2, C B Eom1,2, E E Hellstrom1,2 and D C Larbalestier1,2
Show affiliationsAn important predicted, but so far uncharacterized, property of the new superconductor MgB2 is electronic anisotropy arising from its layered crystal structure. Here we report on three c-axis oriented thin films, showing that the upper critical field anisotropy ratio Hc2
/Hc2
is 1.8 to 2.0, the ratio increasing with higher resistivity. Measurements of the magnetic field-temperature phase diagram show that flux pinning disappears at H*≈0.8Hc2(T) in untextured samples. Hc2(0) is strongly enhanced by alloying to 39 T for the highest resistivity film, more than twice that seen in bulk samples.
- PACS
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74.70.Ad Metals; alloys and binary compounds (including A15, MgB2, etc.)
74.25.Op Mixed states, critical fields, and surface sheaths
74.25.Dw Superconductivity phase diagrams
74.25.Fy Transport properties (electric and thermal conductivity, thermoelectric effects, etc.)
- Subjects
- Dates
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Issue 6 (June 2001)
Received 30 April 2001
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Electronic anisotropy, magnetic field-temperature phase diagram and their dependence on resistivity in c-axis oriented MgB2 thin films
S Patnaik et al 2001 Supercond. Sci. Technol. 14 315
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