X-ray diffraction with photon energies near the Ru L2-absorption edge was used to detect resonant reflections characteristic of a G-type superstructure in RuSr2GdCu2O8 single crystals. A polarization analysis confirms that these reflections are due to magnetic order of Ru moments, and the azimuthal-angle dependence of the scattering amplitude reveals that the moments lie along a low-symmetry axis with substantial components parallel and perpendicular to the RuO2 layers. Complemented by susceptibility data and a symmetry analysis of the magnetic structure, these results reconcile many of the apparently contradictory findings reported in the literature.
@article{arxiv.0812.3024,
title = {Magnetic structure of RuSr$_2$GdCu$_2$O$_8$ determined by resonant x-ray diffraction},
author = {B. Bohnenbuck and I. Zegkinoglou and J. Strempfer and C. S. Nelson and H. -H. Wu and C. Schüßler-Langeheine and M. Reehuis and E. Schierle and Ph. Leininger and T. Herrmannsdörfer and J. C. Lang and G. Srajer and C. T. Lin and B. Keimer},
journal= {arXiv preprint arXiv:0812.3024},
year = {2009}
}