1304.4195 (Randy S. Fishman)

Field dependence of the Spin State and Spectroscopic Modes of
Multiferroic BiFeO$_3$    [PDF]

Randy S. Fishman

The spectroscopic modes of BiFeO$_3$ provide detailed information about the very small anisotropy and Dzyaloshinskii-Moriya (DM) interactions responsible for the long-wavelength, distorted cycloid that appears below $\TN = 640$ K. A microscopic model that includes two DM interactions and easy-axis anisotropy is able to closely describe both the zero-field spectroscopic modes as well as their splitting and evolution in a magnetic field. While only six modes are optically active in zero field, all of the zone-center modes are activated by a magnetic field. The close agreement with experiment suggests that the proposed model provides the foundation for future technological applications of this multiferroic material.

View original: http://arxiv.org/abs/1304.4195