Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 48: Superconductivity: Tunnelling, Josephson Junctions, SQUIDs 2

TT 48.9: Vortrag

Mittwoch, 22. März 2017, 17:15–17:30, HSZ 201

Dielectric properties of disordered thin-film AlO_x — •Arnold Seiler¹, Saskia Meissner¹, Hannes Rotzinger¹, Stefan Fritz², and Georg Weiss¹ — ¹Physikalisches Institut, Karlsruher Institut für Technologie — ²Laboratorium für Elektronenmikroskopie, Karlsruher Institut für Technologie

The nature of atomic tunneling systems (TS) in disordered thin-film dielectric aluminium oxide layers is of great interest. Combined investigation of a variety of fabrication techniques, microstructure analysis of the resulting material, particularly HR-TEM, and measurements of the bulk dielectric properties may give a hint on the nature of the defects.

In this report dielectric measurements in a wide frequency range are presented in order to shed light on the distribution of tunneling systems in AlO_x thin-films and their relaxation to phonons.

Resonant absorption for selected frequencies in the range of 1-6GHz yield the TS density in narrow bands whereas the temperature dependence of the dielectric function gives information on a broad energy range of TS. In the kHz frequency range the application of a magnetic field has a large impact on the dielectric properties which may be a hint that the TS are preferrably located close to the electrodes and interact with quasiparticles.