Optical properties and magnetochromism in multiferroic BiFeO3

Authors

X. S. Xu, University of Nebraska-LincolnFollow
T. V. Brinzari, University of Tennessee, Knoxville
S. Lee, Rutgers University
Y. H. Chu, University of California - Berkeley
L. W. Martin, University of California - BerkeleyFollow
A. Kumar, Pennsylvania State University
S. McGill, National High Magnetic Field Laboratory
R. C. Rai, Buffalo State College
R. Ramesh, University of California - Berkeley
V. Gopalan, Pennsylvania State University
S. W. Cheong, Rutgers University
J. L. Musfeldt, University of Tennessee, Knoxville

Date of this Version

2009

Document Type

Article

Citation

PHYSICAL REVIEW B 79, 134425 (2009)

Comments

Used by permission.

Abstract

In order to investigate spin-charge coupling in multiferroic oxides, we measured the optical properties of BiFeO₃. Although the direct 300 K charge gap is observed at 2.67 eV, absorption onset actually occurs at much lower energy with Fe³⁺ 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-fieldtemperature phase diagram which demonstrates optical evidence for spin spiral quenching above 20 T and suggests a spin domain reorientation near 10 T.