Dresden 2003 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 14: Postersitzung III (Neue u. unkonventionelle Supraleiter, Anwendungen der Supraleitung, Dünne Schichten, JJs und SQUIDs, Schwere Fermionen, Kondo-Systeme)
TT 14.1: Poster
Mittwoch, 26. März 2003, 14:30–19:00, P2c
Thermally Assisted Flux Flow In MgB2 Thin Films — •S. Klimm1, A. Sidorenko1,2, V. Zdravkov2, V. Ryazanov3, R. Tidecks1, S. Horn1, C. Müller1, and A. Wixforth1 — 1Institut f. Physik, Universität Augsburg, 86159 Augsburg, Germany — 2Institute of Applied Physics, 2028 Kishinev, Moldova — 3Institute of Solid State Physics, 142432 Chernogolovka, Russia
The recent discovery of superconductivity in MgB2 [1] raised the questions about the mechanism generating the superconducting state in this compound. The investigation of the problem of the transition to the normal state in a strong magnetic field is important for further applications of MgB2. We prepared thin MgB2 films by DC magnetron sputtering onto MgO and sapphire substrates using a two-step process [2]. The origin of the resistive transition broadening in a magnetic field perpendicular to the film plane has been investigated. Thermally activated flux flow is found to be the mechanism responsible for the resistivity at the lower part of the transition. The unusually strong field dependence of the flux-creep activation energy, U , ranging from U/kB=300 K in low magnetic field, 0<B<1 T, up to U/kB=10000 K in the high field region, is discussed.
This work was partially supported by INTAS (Project Nr.99-00585).
[1] J. Namagatsu, N. Nagakawa, T. Muranaka, Y. Zenitani, J. Akimitsu. Nature 410, 63 (2001).
[2] A. S. Sidorenko, L. R. Tagirov, A. N. Rossolenko, V. V. Ryazanov, M. Klemm, R. Tidecks. Europhys. Lett. 59, 272 (2002).