Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 31: Correlated Electrons: Other Materials
TT 31.6: Vortrag
Dienstag, 21. März 2017, 15:15–15:30, HSZ 103
Electron spin resonance of the spin chain compound Cu(py)2Br2: An experimental and theoretical study — Julian Zeisner1, Stephan Zimmermann1, Vladislav Kataev1, •Michael Brockmann2, Frank Göhmann2, Andreas Klümper2, and Alexander Weiße3 — 1Leibnitz Insitute for Solid State and Material Research, Dresden, Germany — 2University of Wuppertal, Germany — 3Max Planck Institute for Mathematics, Bonn, Germany
We analyze electron spin resonance (ESR) data of the quasi-one-dimensional magnet Cu(py)2Br2 and compare with theoretical predictions for the spin-1/2 Heisenberg chain with small anisotropic perturbations.
Based on measurements of the angular dependence of resonance shift and linewidth at high temperatures the full g-tensor can be determined and the existence of two anisotropy axes oriented perpendicular to the chain axes is proposed. We further estimate the strength of the anisotropy from several ESR data, in particular from the frequency dependence of the resonance shift at low temperatures, showing that usual field theoretical approaches at zero temperature are not sufficient to explain our low-temperature data. Furthermore, from the angular dependence of the linewidth, the algebraic decay of dynamical correlation functions of the isotropic spin chain can be deduced (∼ t−2/3). This result does not agree with the picture of spin diffusion in one dimension (∼ t−1/2).