Magnetic structure of RuSr$_2$GdCu$_2$O$_8$ determined by resonant x-ray diffraction

TL;DR

This study uses resonant x-ray diffraction to determine the magnetic structure of RuSr$_2$GdCu$_2$O$_8$, revealing the orientation of Ru magnetic moments and clarifying previous conflicting reports.

Contribution

It provides the first detailed magnetic structure determination of RuSr$_2$GdCu$_2$O$_8$ using resonant x-ray diffraction and polarization analysis.

Findings

Ru moments lie along a low-symmetry axis with components parallel and perpendicular to RuO$_2$ layers.

Resonant reflections confirm magnetic order of Ru moments.

Results reconcile previous contradictory findings in the literature.

Abstract

X-ray diffraction with photon energies near the Ru L$_2$-absorption edge was used to detect resonant reflections characteristic of a G-type superstructure in RuSr$_2$GdCu$_2$O$_8$ 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 RuO$_2$ 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.