Ferroelectric properties in magnetic fields of varying magnitude and direction have been investigated for a triangular-lattice helimagnet CuFe1-xGaxO2 (x=0.035). The magnetoelectric phase diagrams were deduced for magnetic fields along [001], [110], and [1-10] direction, and the in-plane magnetic field was found to induce the rearrangement of six possible multiferroic domains. Upon every 60-degree rotation of in-plane magnetic field around the c-axis, unique 120-degree flop of electric polarization occurs as a result of the switch of helical magnetic q-vector. The chirality of spin helix is always conserved upon the q-flop. The possible origin is discussed in the light of the stable structure of multiferroic domain wall.
@article{arxiv.0906.0324,
title = {Magnetic digital flop of ferroelectric domain with fixed spin chirality in a triangular lattice helimagnet},
author = {S. Seki and H. Murakawa and Y. Onose and Y. Tokura},
journal= {arXiv preprint arXiv:0906.0324},
year = {2015}
}