Relationship between Magnetic Structure and Ferroelectricity of LiVCuO4

TL;DR

This study investigates how the magnetic structure of LiVCuO4 influences its ferroelectric properties, revealing a close relationship between magnetic order and ferroelectric polarization under varying magnetic fields.

Contribution

It provides experimental evidence linking magnetic structure changes to ferroelectricity in LiVCuO4, including the spin flop transition and polarization suppression under magnetic fields.

Findings

Ferroelectric polarization is suppressed above 2 T magnetic field.

Helical magnetic structure confirmed at zero field and altered by magnetic field.

Polarization correlates with neutron magnetic scattering intensity.

Abstract

Neutron scattering studies and measurements of the dielectric susceptibility and ferroelectric polarization P have been carried out in various magnetic fields H for single-crystal samples of the multiferroic system LiVCuO4 with quasi one-dimensional spin 1/2 Cu2+ chains formed of edge-sharing CuO4 square planes, and the relationship between the magnetic structure and ferroelectricity has been studied. The ferroelectric polarization is significantly suppressed by the magnetic field H above 2 T applied along a and b axes. The helical magnetic structure with the helical axis parallel to c has been confirmed in H=0, and for H//a, the spin flop transition takes place at H=2 T with increasing H, where the helical axis changes to the direction parallel to H. The ferroelectric polarization along a at H=0 is found to be proportional to the neutron magnetic scattering intensity, indicating that the magnetic order is closely related to the appearance of the ferroelectricity. The relationship between the magnetic structure and ferroelectricity of LiVCuO4 is discussed by considering the existing theories.