Browsing by Author "Rai, R. C."

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Optical properties and magnetochromism in multiferroic BiFeO(3)
(2009-04-01)
Xu, X. S.
;
Brinzari, T. V.
;
Lee, S.
;
Chu, Y. H.
;
Martin, L. W.
In order to investigate spin-charge coupling in multiferroic oxides, we measured the optical properties of BiFeO(3). Although the direct 300 K charge gap is observed at 2.67 eV, absorption onset actually occurs at much lower energy with Fe(3+) 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.
Optical properties and magnetochromism in multiferroic BiFeO3
(2009-04-01)
Xu, X. S.
;
Brinzari, T. V.
;
Lee, S.
;
Chu, Y. H.
;
Martin, L. W.
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-field-temperature phase diagram which demonstrates optical evidence for spin spiral quenching above 20 T and suggests a spin domain reorientation near 10 T.