Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 23: Posters Superconductivity, Solids at Low Temperature
TT 23.48: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU D
Intrinsic Josephson effects in the ferromagnetic superconductor RuSr2GdCu2O8 — •T. Nachtrab1, D. Koelle1, R. Kleiner1, C. T. Lin2, C. Bernhard2, R. Koch3, and P. Müller3 — 1Physikalisches Institut - Experimentalphysik II, Universität Tübingen, 72076 Tübingen — 2Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart — 3Physikalisches Institut III, Universität Erlangen-Nürnberg, 91058 Erlangen
The crystal lattice of the ruthenocuprate RuSr2GdCu2O8 (Ru1212) can be described as an alternating stack of weakly ferromagnetic (Tmag ≈ 130 K) RuO2 and superconducting (Tc ≈ 55 K) CuO2 layers, separated by an insulating barrier of SrO. Besides the existence of an intrinsic Josephson effect as, e.g., in Bi2Sr2CaCu2O8+δ (Bi2212), more exotic phenomena, like the formation of intrinsic π-junctions, have been predicted due to the coexistence of ferromagnetism and superconductivity.
We present magnetization and electrical interlayer transport measurements on micron-sized single crystals of Ru1212. The magnetization data differ from former results on polycrystalline samples, confirming the anisotropic structure of the system. The transport measurements show clear evidence for an intrinsic Josephson effect below Tc [1]. Data obtained in magnetic fields reveal that fluxon motion takes place in a very similar fashion as in Bi2212. Although the RuO2 subsystem gives a clear fingerprint in the transport data near Tmag, we did not observe any unconventional behavior due to the interplay of magnetism and superconductivity at low temperatures.
[1] T. Nachtrab et al., Phys. Rev. Lett. 92, 117001 (2004)