By means of electron spin resonance investigations we revealed the crucial role of the interchain coupling in the spin dynamics of the spin-1/2 Heisenberg antiferromagnetic (AF) chain material copper-pyrazine-dinitrate, Cu(C4H4N2)(NO3)2. We found that the dominating interchain interaction is of a zig-zag type. This interaction gives rise to geometrical frustration effects and strongly influences the character of AF ordering. Combining our experimental findings with the results of a quasiclassical approach we argue that at low temperatures the system orders in an incommensurate spiral state.
@article{arxiv.1212.6308,
title = {ESR of coupled spin-1/2 chains: unveiling zig-zag-type interchain correlations},
author = {A. A. Validov and M. Ozerov and J. Wosnitza and S. A. Zvyagin and M. M. Turnbull and C. P. Landee and G. B. Teitel'baum},
journal= {arXiv preprint arXiv:1212.6308},
year = {2013}
}