Magnetic structure of the edge-sharing copper oxide chain compound NaCu2O2

TL;DR

This study uses neutron diffraction to reveal the complex elliptical helix magnetic structure of NaCu2O2, a copper oxide chain compound, and discusses its implications for multiferroic properties.

Contribution

The paper provides the first detailed determination of the incommensurate magnetic structure of NaCu2O2 using neutron diffraction and group-theoretical analysis.

Findings

Elliptical helix magnetic structure identified

Helicity and polarization alternate among chains

Supports multiferroic behavior in copper-oxide chains

Abstract

Single-crystal neutron diffraction has been used to determine the incommensurate magnetic structure of NaCu2O2, a compound built up of chains of edge-sharing CuO4 plaquettes. Magnetic structures compatible with the lattice symmetry were identified by a group-theoretical analysis, and their magnetic structure factors were compared to the experimentally observed Bragg intensities. In conjunction with other experimental data, this analysis yields an elliptical helix structure in which both the helicity and the polarization plane alternate among copper-oxide chains. This magnetic ground state is discussed in the context of the recently reported multiferroic properties of other copper-oxide chain compounds.