Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 9: SC: Poster Session

TT 9.17: Poster

Montag, 22. März 2010, 14:00–18:00, Poster A

Superconductivity in Na_1−xCoO₂·yH₂O thin films — •Sandra Hildebrandt¹, Philipp Komissinkiy¹, Ingo Fritsch², Hanns-Ulrich Habermeier², Peter Lemmens³, and Lambert Alff¹ — ¹Institute for Materials Science, TU Darmstadt — ²Max Planck Institute for Solid State Research, Stuttgart — ³Institute for Condensed Matter Physics, TU Braunschweig

Sodium cobaltate (Na_1−xCoO₂) is a novel material with thermoelectric behavior, charge and spin ordered states dependent on the sodium content in the composition. A superconducting phase was found in water intercalated sodium cobaltate (Na_1−xCoO₂·yH₂O) with x = 0.65 - 0.7 and y = 0.9 - 1.3. The pairing state is still under debate, but there are some indications for a spin-triplet or p-wave superconducting pairing state. First films of Na_1−xCoO₂·yH₂O with a superconducting transition temperature near 5 K have been successfully grown. Here we report on thin films of Na_1−xCoO₂ grown by pulsed laser deposition technique. The deposition parameters, sodium deintercalation and water intercalation conditions are tuned in order to obtain the superconducting phase. The instability of this phase might be an indication for triplet superconductivity, which is known to be affected strongly by impurities and defects.This observation is in agreement with the fact that so far also no superconducting thin films of the most famous triplet superconductor Sr₂RuO₄ have been reported.