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TT: Tiefe Temperaturen

TT 8: Postersitzung I: Supraleitung

TT 8.1: Poster

Montag, 8. März 2004, 14:30–19:00, Poster A

In-situ deposition of MgB₂ thin films by magnetron sputtering and thermal evaporation — •R. Schneider, A.G. Zaitsev, J. Geerk, G. Linker, and F. Ratzel — Forschungszentrum Karlsruhe, Institut für Festkörperphysik

We report on two approaches to the in-situ synthesis of superconducting MgB₂ thin films. In the first approach, Mg and B were simultaneously sputtered from two separate planar targets. The substrate temperature T_s was limited to a small range of 290 to 320^∘C. The resulting films on sapphire substrates were c-axis textured with low growth quality. Their transition temperature T_c reached a maximum of 24 K with a transition width of 0.6 K. A short-time in-situ annealing at 600^∘C improved T_c to 28 K. In the second approach, the Mg sputter source was replaced by a specially designed Mg evaporator. Due to this intense Mg source T_s could be increased to 440^∘C, and T_c of the ”as-grown” films rose to 33 K. Short-time in-situ annealing after the film deposition enhanced T_c to 36 K. For these films we also measured a high critical current density of 15 MA/cm² at 6 K.