Abstract
The ab -plane infrared and optical reflectance of single-crystal Bi2 Sr2 CoO6+δ (0.4<δ<0.5) have been measured over a wide frequency range (50-55000 cm-1) and at temperatures between 20 and 330 K. The room-temperature infrared spectrum displays an insulating characteristic. The optical gap determined from the infrared conductivity (∼0.53 eV) is consistent with thermal activation energy from dc transport measurements. Upon passing through the 265 K antiferromagnetic ordering transition, a softening of the phonon mode near 205 cm-1 correlates well with the temperature-dependent normalized square of the sublattice magnetization. Furthermore, the magnetic-order-induced splitting of the phonon modes at about 238 and 376 cm-1 is observed. Additionally, the phonon mode at about 588 cm-1 exhibits a Fano-type line shape. Since no appreciable structural change was detected at low temperatures in x-ray diffraction studies, all of these observables suggest a complex nature of spin-phonon coupling in this material.
| Original language | English |
|---|---|
| Article number | 155109 |
| Journal | Physical Review B - Condensed Matter and Materials Physics |
| Volume | 79 |
| Issue number | 15 |
| DOIs | |
| Publication status | Published - 2009 Apr 1 |
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ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
Cite this
Spin-phonon coupling in antiferromagnetic Bi2 Sr2 CoO6+δ : An infrared reflectance study. / Hsu, H. C.; Chou, F. C.; Koyama, K.; Watanabe, K.; Liu, Hsiang Lin.
In: Physical Review B - Condensed Matter and Materials Physics, Vol. 79, No. 15, 155109, 01.04.2009.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Spin-phonon coupling in antiferromagnetic Bi2 Sr2 CoO6+δ
T2 - An infrared reflectance study
AU - Hsu, H. C.
AU - Chou, F. C.
AU - Koyama, K.
AU - Watanabe, K.
AU - Liu, Hsiang Lin
PY - 2009/4/1
Y1 - 2009/4/1
N2 - The ab -plane infrared and optical reflectance of single-crystal Bi2 Sr2 CoO6+δ (0.4<δ<0.5) have been measured over a wide frequency range (50-55000 cm-1) and at temperatures between 20 and 330 K. The room-temperature infrared spectrum displays an insulating characteristic. The optical gap determined from the infrared conductivity (∼0.53 eV) is consistent with thermal activation energy from dc transport measurements. Upon passing through the 265 K antiferromagnetic ordering transition, a softening of the phonon mode near 205 cm-1 correlates well with the temperature-dependent normalized square of the sublattice magnetization. Furthermore, the magnetic-order-induced splitting of the phonon modes at about 238 and 376 cm-1 is observed. Additionally, the phonon mode at about 588 cm-1 exhibits a Fano-type line shape. Since no appreciable structural change was detected at low temperatures in x-ray diffraction studies, all of these observables suggest a complex nature of spin-phonon coupling in this material.
AB - The ab -plane infrared and optical reflectance of single-crystal Bi2 Sr2 CoO6+δ (0.4<δ<0.5) have been measured over a wide frequency range (50-55000 cm-1) and at temperatures between 20 and 330 K. The room-temperature infrared spectrum displays an insulating characteristic. The optical gap determined from the infrared conductivity (∼0.53 eV) is consistent with thermal activation energy from dc transport measurements. Upon passing through the 265 K antiferromagnetic ordering transition, a softening of the phonon mode near 205 cm-1 correlates well with the temperature-dependent normalized square of the sublattice magnetization. Furthermore, the magnetic-order-induced splitting of the phonon modes at about 238 and 376 cm-1 is observed. Additionally, the phonon mode at about 588 cm-1 exhibits a Fano-type line shape. Since no appreciable structural change was detected at low temperatures in x-ray diffraction studies, all of these observables suggest a complex nature of spin-phonon coupling in this material.
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U2 - 10.1103/PhysRevB.79.155109
DO - 10.1103/PhysRevB.79.155109
M3 - Article
AN - SCOPUS:65649139595
VL - 79
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 15
M1 - 155109
ER -