Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 6: Postersession Correlated Electrons: (General) Theory, Low-Dimensional Systems, Kondo Physics, Heavy Fermions, Quantum-Critical Phenomena
TT 6.67: Poster
Montag, 23. März 2009, 13:00–16:45, P1A
Low frequency spin dynamics in the S=1/2 Heisenberg chain compound Cu(C4H4N2)(NO3)2 (CuPzN) measured by 13C- and 14N-NMR spectroscopy — •M. Günther1, H. Kühne1,2, H.-H. Klauß1, M. Falkner2, J. Litterst2, S. Grossjohann3, W. Brenig3, A.P. Reyes4, P.L. Kuhns4, C.P. Landee5, and M.M. Turnbull5 — 1IFP, TU Dresden — 2IPKM, TU Braunschweig — 3ITHP, TU Braunschweig — 4NHMFL, FSU, USA — 5DPC, Clark University, USA
The local magnetization and low frequency magnetic dynamics of the antiferromagnetic S=1/2 Heisenberg chain compound CuPzN have been explored both theoretically and experimentally by means of 13C-NMR spectroscopy for the full B vs. T phase diagram with a critical field of B=14.9T [1]. With an in general very satisfying agreement between experiment and theory, we found a divergence of the low frequency spin dynamics in the critical field regime and a spin gap opening linear with field in the saturated phase. On our poster, we also present NMR studies of the 14N-site in the nitrate groups. Since the 14N-nucleus has a finite quadrupole moment, fluctuations of the electrical field gradient(EFG) tensor become visible in the experiment. By analysis of the angular dependence of the NMR properties it is possible to distinguish between the magnetic and EFG fluctuations for the data presented at temperatures between 2K and 55K and fields B<7T.
[1] H. Kuehne et al., arXiv:0804.2170.