Magnetic structure in the antiferromagnetic state of DCNQI-Cu salts

The antiferromagnetic (AF) state of (DMe-DCNQI[3,3:1]d7)2Cu has been investigated microscopically by the measurements of 1H-NMR lineshapes and antiferromagnetic resonance (AFMR) on a single crystal sample. NMR line in the AF state was found to be composed of well-separated three pairs of peaks, while the 1H has a unique crystallographic site. From the angular dependence of the peak positions, the magnetic structure is determined; i) the Cu2+ ions are localized with three-fold periodicity, ii) the AF moments reside only at Cu2+ site, and iii) the hard axis of AF state is the c-axis. The angular dependence of AFMR field indicates that the easy axis is in the ab-plane and parallel to the symmetry axis of CN tetragon coordinating axis.