Magneto-electric multiferroics exemplified by TbMnO3 possess both magnetic and ferroelectric long-range order. The magnetic order is mostly understood, whereas the nature of the ferroelectricity has remained more elusive. Competing models proposed to explain the ferroelectricity are associated respectively with charge transfer and ionic displacements. Exploiting the magneto-electric coupling, we use an electric field to produce a single magnetic domain state, and a magnetic field to induce ionic displacements. Under these conditions, interference charge-magnetic X-ray scattering arises, encoding the amplitude and phase of the displacements. When combined with a theoretical analysis, our data allow us to resolve the ionic displacements at the femtoscale, and show that such displacements make a significant contribution to the zero-field ferroelectric moment.
@article{arxiv.1110.2875,
title = {Femtoscale magnetically induced lattice distortions in multiferroic TbMnO3},
author = {H. C. Walker and F. Fabrizi and L. Paolasini and F. de Bergevin and J. Herrero-Martin and A. T. Boothroyd and D. Prabhakaran and D. F. McMorrow},
journal= {arXiv preprint arXiv:1110.2875},
year = {2011}
}
Comments
This is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science VOL 333, (2011), doi:10.1126/science.1208085