Regensburg 2010 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
TT: Fachverband Tiefe Temperaturen
TT 38: CE: Quantum-Critical Phenomena 2
TT 38.1: Talk
Friday, March 26, 2010, 10:15–10:30, H18
Low field spin dynamics of a Cu(II) S=1/2 antiferromagnetic Heisenberg chain studied by 14N-NMR spectroscopy — •Marco Günther1, Hannes Kühne1, Matthias Falkner2, Hans-Henning Klauß1, K. Doll3, C.P. Landee4, and M.M. Turnbull4 — 1Institut für Festkörperphysik, TU Dresden — 2Institut für Physik der Kondensierten Materie, TU Braunschweig — 3Institut für Mathematische Physik, TU Braunschweig — 4DPC, Clark University, Worcester, USA
By means of 14N-NMR spectroscopy we study the low field NMR frequency shift and electronic spin dynamics in Cu(C4H4N2)(NO3)2 (CuPzN), which is one of the best experimental realizations of the antiferromagnetic S=1/2 Heisenberg chain model.
The observed pattern of angular dependent NMR frequencies is disentangled into magnetic and quadrupolar contributions. The electric field gradient tensor is determined and compared to density functional calculations at the nitrogen site. A comparison of the magnetic part of the NMR shift to a local dipole model of the electronic moments allows to construct the full hyperfine coupling tensor.
The experimentally observed anisotropy of the nuclear spin-lattice relaxation rate T1−1 can be modulated with purely magnetic fluctuations, i.e. an isotropic dynamic structure factor and the magnetic coupling tensor derived from the static properties. Our results are compared with previous 13C-NMR data in the low field regime of CuPzN [1].
[1] Kühne et al., Phys. Rev. B 80, 045110 (2009)