Muon spin rotation and resonant soft X-ray scattering experiments on prototype multiferroics RMn2O5 (R = Y, Sm) are used to demonstrate that the local electric displacements are driven by the spin-current (SC) mechanism. Small local electric displacements were evaluated by observing spin polarization at ligand O ions, for which implanted muons served as an extremely sensitive probe. Our results for YMn2O5 provide evidence that the spin polarization of O ions forming a spin cycloid chain with Mn spins increases in proportion to the vector spin chirality (Si x Sj ) of the Mn ions. This relationship strongly indicates that the charge transfer between O and Mn ions is driven by the SC mechanism, which leads to the ferroelectricity accompanying O spin polarization.
@article{arxiv.2006.15834,
title = {Electronic charge transfer driven by spin cycloidal structure},
author = {Y. Ishii and S. Horio and Y. Noda and M. Hiraishi and H. Okabe and M. Miyazaki and S. Takeshita and A. Koda and K. M. Kojima and R. Kadono and H. Sagayama and H. Nakao and Y. Murakami and H. Kimura},
journal= {arXiv preprint arXiv:2006.15834},
year = {2020}
}