Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 32: Correlated Electrons: Poster Session
TT 32.76: Poster
Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B
High-field Gd3+–ESR on the spin-antiferromagnet GdNi2B2C — •Uwe Schaufuß1, Ferenc Murányi1, Vladislav Kataev1, Mathias Dörr2, Martin Rotter3, and Bernd Büchner1 — 1IFW Dresden, Institute for Solid State Research — 2Institut für Festkörperphysik, Technische Universität Dresden — 3Institute for Physical Chemistry, University of Vienna, Austria
The layered metalic compounds RNi2B2C (R = rare earth ions) attracted attention in the last years for its rich TH–phase diagrams. superconductivity and antiferromagnetic (afm) ordering with commensurate or incomensurate spin structure can be found in this material family. In order to obtain a deeper insight in the magnetic interactions in the spin-only antiferromagnet GdNi2B2C we have performed Gd3+–electron spin resonance study in a frequency range 10−350 GHz on a single crystal of this material. The main crystalographic axes were successively set parallel to the magnetic field. We found that the Korringa relaxation rate was surprisingly anisotropic implying anisotropic interactions between the localized Gd3+-spins and the conduction electrons. In the afm state we observed a large isotropic afm-gap of 76 GHz which is much larger than expected from the dipole-dipole interaction. This gap is field dependent and vanishes in strong fields. We will discuss possible reason for the unusual magnetic anisotropy in GdNi2B2C.
The work was supported by the DFG through SFB 463.