Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 32: Postersession II: Spinstruct./Phase Trans. (1-10); Spinelectronics (11-15); Thin Films (16 - 36); Particles/Clusters (37-45); Multiferroics (46-54); Spindynamics/Spin Torque (55 - 76); Post Deadlines (77-79)

MA 32.70: Poster

Freitag, 29. Februar 2008, 11:15–14:00, Poster E

Unusual NMR linebroadening and spin lattice relaxation in the Ca-doped S=1/2 spin chain compound SrCuO₂ — •Franziska Hammerath, Hans-Joachim Grafe, Anja Wolter, Vladislav Kataev, Patrick Ribeiro, Christian Hess, and Bernd Büchner — IFW Dresden, Institut für Festkörperforschung, Postfach 270116, 01171 Dresden

We present ^63,65Cu Nuclear Magnetic Resonance (NMR) measurements on undoped SrCuO₂ and Ca doped Sr_0.9Ca_0.1CuO₂ single crystals. The crystal structure contains one dimensional CuO₂ double chains that are magnetically decoupled. The system orders magnetically only below 1.5 K. Nevertheless, the Cu NMR spectra broaden already at temperatures below 100 K and show an anomalous two peak structure at low temperatures. For the Ca doped sample, this broadening is reduced. The reason for this unusual broadening is not known, but a similar broadening has been reported for the single chain compound Sr₂CuO₃. The spin lattice relaxation rate, 1/T₁, is temperature independent. This is typical for spin chains and has also been reported for Sr₂CuO₃. Surprisingly, non-magnetic Ca induces a gap like behaviour in 1/T₁.