Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 36: Postersitzung (Elektronische Struktur, Grenzfl
äche fest-flüssig, Halbleiteroberfl
ächen und -grenzfl
ächen, Nanostrukturen, Oberfl
ächenreaktionen, Teilchen und Cluster, Struktur und Dynamik reiner Oberfl
ächen)

O 36.68: Poster

Montag, 7. März 2005, 15:00–18:00, Poster TU F

Superconducting properties of cluster-assembled Pb-films — •M.J. Van Bael, D.N. Ievlev, A.N. Dobrynin, C. Hendrich, K. Temst, V.V. Moshchalkov, and P. Lievens — Laboratorium voor Vaste-Stoffysica en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium

We have prepared Pb cluster assembled films and studied their superconducting properties. The clusters were produced in a laser vaporization cluster source and deposited at low kinetic energy (<1 eV/atom) at UHV conditions [1, 2]. The mass abundance distribution was monitored by time-of-flight mass spectrometry. By changing the source parameters the mass distribution peak was shifted in the range from 100 to 1500 atoms per cluster. The superconducting properties of the Pb-cluster films were measured in a SQUID magnetometer and by ac-susceptibility. Pb is a superconducting material with a bulk critical temperature of 7.2K. A reduced critical temperature is observed in the cluster-assembled Pb films. We have measured the superconducting phase boundary and magnetic hysteresis curves with the applied magnetic field parallel and perpendicular to the film plane. The dependence of the superconducting properties on the size of the constituent clusters will be discussed.

[1] N. Vandamme, E. Janssens, F. Vanhoutte, P. Lievens, C. Van Haesendonck, J. Phys.: Cond. Matter 15, S2983 (2003).

[2] W. Bouwen, P. Thoen, F. Vanhoutte, S. Bouckaert, F. Despa, H. Weidele, R.E. Silverans, and P. Lievens, Rev. Sci. Instrum. 71, 54 (2000).