Structure and ferroelectric properties of [C3N2H5]5[Bi2Br11]

被引：59

作者：

Piecha, A. ^{[1
]}

Bialonska, A. ^{[1
]}

Jakubas, R. ^{[1
]}

机构：

[1] Univ Wroclaw, Fac Chem, PL-50383 Wroclaw, Poland

来源：

JOURNAL OF PHYSICS-CONDENSED MATTER | 2008年 / 20卷 / 32期

关键词：

D O I：

10.1088/0953-8984/20/32/325224

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

A ferroelectric crystal [C3N2H5](5)[Bi2Br11] has been synthesized and structurally characterized at 170 and 100 K. The crystal structure consists of discrete corner-sharing bioctahedra [Bi2Br11](5-) and highly disordered imidazolium cations. The room temperature crystal structure has been determined as monoclinic, space group, P2(1)/n with: a = 9.257(2) angstrom, b = 15.157(3) angstrom, c = 13.865(3) angstrom and beta = 97.73(3)degrees. The crystal undergoes two solid-solid phase transitions: at 355 K of first-order and at 155 K of second-order type. The later transition takes place between monoclinic phases: P2(1)/n -> Pn. The dielectric and pyroelectric measurements allow us to characterize the low temperature phase III as ferroelectric with the Curie temperature at 155 K. The saturated spontaneous polarization of the order of 2.6 x 10(-3) C m(-2) was measured along the a-axis (130 K). The ferroelectric phase transition mechanism at 155 K is due to the dynamics of three of five nonequivalent imidazolium cations.

引用

页数：9

共 26 条

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