By combining bulk properties, neutron diffraction and non-resonant X-ray diffraction measurements, we demonstrate that the new multiferroic Cu3Nb2O8 becomes polar simultaneously with the appearance of generalised helicoidal magnetic ordering. The electrical polarization is oriented perpendicularly to the common plane of rotation of the spins --- an observation that cannot be reconciled with the "conventional" theory developed for cycloidal multiferroics. Our results are consistent with coupling between a macroscopic structural rotation, which is allowed in the paramagnetic group, and magnetically-induced structural chirality.
@article{arxiv.1106.4699,
title = {Cu3Nb2O8: a multiferroic with chiral coupling to the crystal structure},
author = {R. D. Johnson and Sunil Nair and L. C. Chapon and A. Bombardi and C. Vecchini and D. Prabhakaran and A. T. Boothroyd and P. G. Radaelli},
journal= {arXiv preprint arXiv:1106.4699},
year = {2015}
}
Comments
This article is in print with Physical Review Letters