Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 33: Superconductivity, Measuring Devices, Matter at Low Temperature: Poster Session

TT 33.38: Poster

Mittwoch, 28. März 2012, 15:00–19:00, Poster B

Preparation and characterization of LaAlO₃/SrTiO₃ heterostructures — •Ahmed Sleem^1,2, Dirk Fuchs¹, Rudolf Schneider¹, and Hilbert von Löhneysen^1,3 — ¹Karlsruher Institut für Technologie, Institut für Festkörperphysik, 76021 Karlsruhe, Germany — ²Karlsruher Institut für Technologie, Fakultät für Physik, 76031 Karlsruhe, Germany — ³Karlsruher Institut für Technologie, Physikalisches Institut, 76031 Karlsruhe, Germany

Thin films of LaAlO₃ were grown epitaxially by pulsed laser deposition on TiO₂ terminated <001> oriented SrTiO₃ substrates. The deposition parameters, i. e., substrate temperature T_S, oxygen partial pressure P(O₂) and the laser fluence F on the target were optimized with respect to the interface conductivity of the heterostructure. For this purpose, contacts through the LaAlO₃ layer were prepared by argon ion-etching down to the interface and subsequent hole-filling with Pt or direct bonding of Al-wires. Metallic behavior down to T = 4.2 K was found only in a very narrow range of T_S, F and P(O₂). Experimental results with respect to the characterization of the surface and substrate termination, the structural properties and interface conductivity obtained by atomic force microscopy, x-ray diffraction and high resolution electron microscopy, and resistivity measurements, respectively, will be presented and discussed.