We have studied the magnetic field dependence of far-infrared active magnetic modes in a single ferroelectric domain \BFO/ crystal at low temperature. The modes soften close to the critical field of 18.8\,T along the [001] (pseudocubic) axis, where the cycloidal structure changes to the homogeneous canted antiferromagnetic state and a new strong mode with linear field dependence appears that persists at least up to 31\,T. A microscopic model that includes two \DM/ interactions and easy-axis anisotropy describes closely both the zero-field spectroscopic modes as well as their splitting and evolution in a magnetic field. The good agreement of theory with experiment suggests that the proposed model provides the foundation for future technological applications of this multiferroic material.
@article{arxiv.1302.2491,
title = {Terahertz spectroscopy of spin waves in multiferroic BiFeO$_3$ in high magnetic fields},
author = {U. Nagel and Randy S. Fishman and T. Katuwal and H. Engelkamp and D. Talbayev and Hee Taek Yi and S. -W. Cheong and T. Rõõm},
journal= {arXiv preprint arXiv:1302.2491},
year = {2013}
}
Comments
Added Randy S. Fishman to the author list, he contributed the theory