Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 39: Correlated Electrons: Heavy Fermions 1

TT 39.11: Vortrag

Donnerstag, 26. März 2009, 12:30–12:45, HSZ 304

Electronic transport properties of c-axis oriented CeCoIn₅ thin films — •Oleksandr Foyevtsov and Michael Huth — Johann Wolfgang Goethe University, Frankfurt am Main, Germany

We report results of the growth of c-axis oriented thin films of the heavy-fermion superconductor CeCoIn₅ prepared by molecular beam epitaxy. The films were grown by co-deposition of the constituent elements on chemically cleaned a-plane α-Al₂O₃ substrates. X-ray (XRD) diffraction, atomic force (AFM) and scanning electron microscopy (SEM) were used for film characterization. The films show a pronounced c-axis growth preference with a moderate tendency for epitaxial in-plane order driven by substrate crystallographic planes. In general the films’ morphology is rough, which we assume is driven by the weak wetting tendency of the In component. Comparative growth studies done on the parent compound CeIn₃ support this assumption. By optimization of the growth process, samples with improved surface morphology were obtained. Electronic transport measurements (resistivity, magneto-resistivity, Hall effect) were performed in the temperature range from 1.8 K to 270 K in magnetic fields up to 9 T. We prepared superconductor-insulator-superconductor tunnel junctions on selected thin films using thin amorphous AlO_x layers as insulating barrier and In layers as counter electrode. These tunnel diodes were prepared in-situ by a stencil mask technique. First results on the tunneling spectroscopy of these diodes will be presented.