Raman scattering investigation of RB6 (R=Ca, La, Ce, Pr, Sm, Gd, Dy, and Yb)
Use this link to cite this item : https://ir.lib.hiroshima-u.ac.jp/00018722
ID | 18722 |
file | |
creator |
Nagai, Shinji
Okamoto, Naoki
Iga, Fumitoshi
Kunii, Satoru
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abstract | The excitation-energy, polarization, and temperature dependeces of Raman scattering spectra have been measured for the RB6 crystals (R=Ca 2+, La3+, Ce3+, Pr3+, Sm 2.6+, Gd3+, Dy3+, and Yb2+). In the divalent crystals of CaB6 and YbB6, the Eg phonon shows doublet, while the line shape is a broad single peak for the trivalent case. In the trivalent crystals, two kinds of the extra peaks have been clearly observed at around 200 cm-1 and at around 1400 cm -1 in addition to the Raman-active phonons and crystal electric-field (CEF) excitations. The peak intensities at around 200 cm -1 show the anomalous decrease with decreasing temperature, and this temperature dependence correlates with that of the mean-square displacement of the R ion. Furthermore, their energies decrease with the increase of the cage space due to B6. These peaks are originated from the second-order excitation of acoustic phonons. The broad peak at around 1400 cm-1 is assigned as the second-order excitation of the T2g phonon. For the T2g phonon, the energy difference and its line-shape change between the trivalent and divalent crystals suggests the existence of electron-phonon interaction. We have observed the CEF excitation in PrB 6 and have obtained the Lea, Leask, and Wolf parameters with x=0.94 and W=9.2 K.
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journal title |
Physical Review B - Condensed Matter and Materials Physics
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volume | Volume 68
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issue | Issue 22
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start page | 224305-1
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end page | 224305-9
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date of issued | 2003-12-30
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publisher | American Physical Society
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issn | 0163-1829
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publisher doi | |
language |
eng
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nii type |
Journal Article
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HU type |
Journal Articles
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DCMI type | text
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format | application/pdf
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text version | publisher
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rights | Copyright (c) 2003 American Physical Society.
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relation url | |
department |
Graduate School of Integrated Arts and Sciences
Graduate School of Advanced Sciences of Matter
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