Regensburg 2004 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Tiefe Temperaturen
TT 14: FV-internes Symposium ”Orbital Physics”
TT 14.3: Vortrag
Dienstag, 9. März 2004, 15:20–15:35, H18
Frustrated orbital ground state in thiospinels — •J. Hemberger, H.-A. Krug von Nidda, V. Fritsch, N. Büttgen, E.-W. Scheidt, P. Lunkenheimer, R. Fichtl, V. Tsurkan, and A. Loidl — Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg
We studied the ground state properties of the normal cubic spinel compounds AB2S4 (A = Fe, Mn and B = Sc, Cr) by means of specific heat, magnetization and susceptibility measurements, as well as dielectric and optical spectroscopy. In all compounds frustration strongly influences the interplay of orbital and magnetic degrees of freedom and corresponding order phenomena. Our results indicate the existence of distinguished spin-orbital scenarios: In the case of nonmagnetic B-sites (Sc) we find strong magnetic coupling (Curie-Weiss temperature θCW= −45 K for A= Fe) without any indications of order down to 50 mK. The ground states of these compounds have to be characterized as a spin liquid in MnSc2S4 and a spin-orbital liquid in FeSc2S4, where Fe2+ is Jahn-Teller active but orbitally frustrated. In the case of magnetic B-sites (Cr) spin-order is induced and the low-temperature states have to be described as orbital liquid, orbital glass, or finally orbital order.