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de Boissieu, M.*; Francoual, S.*; Minalkovi, M.*; 柴田 薫; Baron, A. Q. R.*; Sidis, Y.*; 石政 勉*; Wu, D.*; Lograsso, T.*; Regnault, L.-P.*; et al.
Nature Materials, 6(12), p.977 - 984, 2007/12
被引用回数:44 パーセンタイル:81.54(Chemistry, Physical)局所構造及び(周期性又は準周期性)長距離秩序のそれぞれが格子振動に及ぼす影響を研究する目的でZn-Mg-Sc正20面体準結晶及びZn-Sc周期性1/1近似結晶の単結晶を用いた非弾性中性子,X-ray散乱実験を実施した。全体的な格子振動の相似性や横波分散関係に擬ギャップが共通して存在する等の定性的な相似性を別にすると、準結晶中と近似結晶中の格子振動には定量的な違いが観測された。例えば近似結晶中の格子振動の方が擬ギャップが大きくはっきりしている点である。またこれらの実験結果は精密原子構造モデルと振動型ペアポテンシャルをもとにしたシミュレーションと比較が行われよく再現されることが明らかになった。
柴田 薫; 山田 庸公*; de Boissieu, M.*
no journal, ,
We present a detailed study of Quasielastic Neutron Scattering (QENS) due to the tetrahedron dynamic among the order-disorder phase transition occurring at about Tc = 160 K. The QENS measurements have been performed at around Q = 2.67 [1/A] near the (1/2, 11/2, 2) superstructure reflection and for temperatures ranging from 100 K (i.e. below Tc) to 400 K. The QENS experiments were conducted on the DNA time-of-flight type Si analyzer near backscattering spectrometer installed at the MLF, J-PARC. The spectrometer was operated in high-resolution dE mode and at high momentum transfer Q mode, with an instrumental resolution of dE = 12 micro eV using Si311 analyzer. In the measured QENS spectrum, we observed two relaxation processes, not only the fast process which is characterized several 100 micro eV at the full width at FWHM, but also the slow process which is characterized several 10 micro eV at FWHM.