Pressure induced phase transformation of Ba8Ga 16Ge30 clathrate studied by x-ray diffraction and Raman spectroscopy

Tetsuji Kume, Satoshi Ohno, Shigeo Sasaki, Hiroyasu Shimizu, Yasuo Ohishi, Norihiko L. Okamoto, Kyosuke Kishida, Katsushi Tanaka, Haruyuki Inui

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13 Citations (Scopus)

Abstract

The phase transition and the vibrational properties of Ba 8Ga16Ge30 have been investigated at high pressures up to 40 GPa at room temperature. The combined study of the high-pressure Raman and synchrotron powder x-ray diffraction (XRD) experiments revealed the occurrence of a first-order phase transition at 33 GPa, on which a volume decrease of about 3% was found. Rietveld refinements of the XRD data demonstrated the atomic displacements precursory to the phase transition, allowing us to discuss the mechanism of the phase transition. In the Raman experimental data, anomalies were observed in the spectral feature and the guest vibration around 17 GPa. By combining the Raman results with the XRD ones, the vibrational frequency of the guest Ba was investigated as a function of the host cage size. As a result, a linear relation between guest vibrational frequency and the guest-host distance was identified.

Original languageEnglish
Article number013517
JournalJournal of Applied Physics
Volume107
Issue number1
DOIs
Publication statusPublished - 2010 Feb 5
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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