Abstract
In order to investigate spin-charge coupling in multiferroic oxides, we measured the optical properties of . Although the direct 300 K charge gap is observed at 2.67 eV, absorption onset actually occurs at much lower energy with excitations at 1.41 and 1.90 eV. Temperature and magnetic-field-induced spectral changes reveal complex interactions between on-site crystal-field and magnetic excitations in the form of magnon sidebands. We employ the sensitivity of these magnon sidebands to map out the magnetic-field-temperature phase diagram which demonstrates optical evidence for spin spiral quenching above 20 T and suggests a spin domain reorientation near 10 T.
- Received 17 February 2009
DOI:https://doi.org/10.1103/PhysRevB.79.134425
©2009 American Physical Society