针铁矿（α-FeOOH）纳米棒水悬浮液中磁场诱导的向列柱状相变

Magnetic-field-induced nematic-columnar phase transition in aqueous suspensions of goethite (alpha-FeOOH) nanorods.

作者信息

Lemaire B J, Davidson P, Panine P, Jolivet J P

机构信息

Laboratoire de Physique des Solides, UMR CNRS 8502, Bâtiment 510, Université Paris-Sud, 91405 Orsay, France.

出版信息

Phys Rev Lett. 2004 Dec 31;93(26 Pt 1):267801. doi: 10.1103/PhysRevLett.93.267801. Epub 2004 Dec 20.

DOI:10.1103/PhysRevLett.93.267801

PMID:15698022

Abstract

Colloidal aqueous suspensions of goethite lath-shaped nanorods form nematic and isotropic phases. We show that they also display a 2D rectangular (c2mm) columnar phase at volume fractions phi larger than 15%. Interestingly, the nematic-columnar first-order transition can also be triggered by applying to the nematic phase a magnetic field of intensity decreasing with phi (1 T at 8.5%; 0.5 T at 12%). Single domains of the columnar phase were thus produced and their structure investigated by synchrotron x-ray scattering. This magnetic-field-induced transition is fully reversible and reproducible.

摘要

针铁矿板条状纳米棒的胶态水悬浮液形成向列相和各向同性相。我们发现，在体积分数φ大于15%时，它们还呈现二维矩形（c2mm）柱状相。有趣的是，向列相 - 柱状相的一级转变也可以通过向向列相施加强度随φ降低的磁场来触发（在8.5%时为1 T；在12%时为0.5 T）。由此产生了柱状相的单畴，并通过同步加速器X射线散射研究了它们的结构。这种磁场诱导的转变是完全可逆和可重复的。