Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication
Granularity and Spontaneous Vortex State for the Weakly Ferromagnetic Superconductor RuSr2GdCu2O8
Papageorgiou, T.; Casini, E.; Braun, H. F.; Herrmannsdörfer, T.; Bianchi, A. D.; Wosnitza, J.;
In the high-Tc cuprate RuSr2GdCu2O8 (Ru1212) weak ferromagnetism (T Ru/N ? 130 K) coexists with superconductivity (Tc,conset ? 50 K). This rises the interesting question concerning the formation of a spontaneous vortex state (SVS) in the case that the internal magnetic field is greater than the first critical field Hc1. Recently, the formation of a SVS has been proposed for Ru1212 after the phase diagram for this compound was constructed from dc-magnetization and resistance measurements [1]. We show, by a comparison of resistance with ac-susceptibility and dc-magnetization measurements, where both the intra- and inter-granular superconducting transition are obvious, that the granular nature of the investigated samples has to be carefully considered in the investigations of possible SVS formation. A particular SVS with vortices pinned in the intergrain area is much more likely. Single crystals would be required to unambiguously demonstrate the formation or non-formation of a spontaneaous vortex state in bulk Ru1212.
[1] C. Y. Yang, B. C. Chang, H. C. Ku, Y. Y. Hsu, cond-mat/0507014
  • Poster
    DPG-Frühjahrstagung, 27.-31.03.2006, Dresden, Deutschland

Publ.-Id: 8743 - Permalink