Spin polarization of the magnetic spiral in NaCu_2O_2, as seen by NMR

TL;DR

This study uses ^{23}Na NMR spectroscopy to investigate the incommensurate spin order in NaCu_2O_2, revealing a bc-plane polarized spin spiral, which clarifies previous neutron diffraction results.

Contribution

It provides new insights into the spin spiral polarization in NaCu_2O_2 using NMR, challenging earlier neutron diffraction findings.

Findings

Identified a bc-plane polarized spin spiral in NaCu_2O_2.

Demonstrated incommensurate static magnetic modulation.

Reconciled NMR results with previous neutron data.

Abstract

The incommensurate (IC) spin ordering in quasi-1D edge-shared cuprate NaCu_2O_2 has been studied by ^{23}Na nuclear magnetic resonance spectroscopy in an external magnetic field near 6 Tesla applied along the main crystallographic axes. The NMR lineshape evolution above and below T_N\approx12 K yields a clear signature of an IC static modulation of the local magnetic field consistent with a Cu^{2+} spin spiral polarized in the bc-plane rather than in the ab-plane as reported from earlier neutron diffraction data.