Heterophase fluctuations near $$T_{rm c}$$ in the relaxor ferroelectrics (1-x)Pb(Zn$$_{1/3}$$Nb$$_{2/3}$$)O$$_{3}$$-xPbTiO$$_{3}$$ ($$x$$ = 0.09) studied by X-ray diffuse scattering and coherent X-ray scattering
X線散漫散乱とコヒーレントX線散乱により調べたリラクサー強誘電体91%Pb(Zn$$_{1/3}$$Nb$$_{2/3}$$)O$$_{3}$$-9%PbTiO$$_{3}$$$$T_{rm c}$$近傍におけるヘテロ相ゆらぎ
大和田 謙二; 水木 純一郎*; 松下 三芳*; 並河 一道*
Owada, Kenji; Mizuki, Junichiro*; Matsushita, Mitsuyoshi*; Namikawa, Kazumichi*
X線散漫散乱法とコヒーレントX線散乱法を相補利用し、リラクサー強誘電体91%Pb(Zn$$_{1/3}$$Nb$$_{2/3}$$)O$$_{3}$$-9%PbTiO$$_{3}$$の強誘電相転移(455K)を調べ、その近傍でヘテロ相ゆらぎが発生していることを明らかにした。ヘテロ相ゆらぎは強誘電相転移(1次相転移)の前駆現象であるばかりでなく、低周波誘電応答の起源とも考えられる。
The paraelectric (PE) to ferroelectric (FE) first-order phase transition of 0.91Pb(Zn$$_{1/3}$$Nb$$_{2/3}$$)O$$_{3}$$-0.09PbTiO$$_{3}$$ ($$T_{c}^{c}$$ = 455 K on cooling) has been studied by the complementary use of X-ray diffuse scattering (XDS) and coherent X-ray scattering (CXS). XDS was mainly used to investigate the FE regions, while CXS was mainly used to investigate the PE regions above $$T_{c}^{c}$$ on cooling. The diffuse scattering intensity due to the appearance of FE regions shows a maximum at $$T_{rm max}= 460$$ K. The diffuse scattering is dynamic in nature and the softening trend changes to a hardening trend at $$T_{rm max}$$. This means that the FE instability is maximum at $$T_{rm max}$$ and therefore the FE regions are well stabilized below $$T_{rm max} $$. The spatial autocorrelation function obtained by CXS, corresponding to the texture of PE regions, starts to rapidly change at about $$T_{rm max}$$ and is most unstable at $$T_{c}^{c}$$. We conclude that a heterophase fluctuation occurs between $$T_{c}^{c}$$ and $$T_{rm max}$$ near the phase transition. The heterophase fluctuation can be expected to correlate to the low-frequency dielectric dispersion and contribute to the phase transition as a precursor phenomenon of the first-order phase transition.
使用言語 : English
掲載資料名 : Physical Review B
: 90
: 10
ページ数 : p.104109_1 - 104109_12
発行年月 : 2014/09
出版社名 : American Physical Society
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論文URL :
キーワード : リラクサー強誘電体; コヒーレントX線
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論文解説記事
(成果普及情報誌)
:
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登録番号 : AA20140303
抄録集掲載番号 : 42001314
論文投稿番号 : 14953
Accesses  (From Jun. 2, 2014)
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パーセンタイル:86.74
分野:Physics, Condensed Matter
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