作者:R. Tamura、K. Edagawa、C. Aoki、S. Takeuchi、K. Suzuki
DOI:10.1016/j.jallcom.2003.10.073
日期:2004.9
X-ray and electron diffraction, electrical and thermal property experiments at low temperatures have unambiguously shown that Cd6Yb, Cd6Ca and Cd6Y intermetallics, which are cubic crystals with a similar to 1.5 nm, undergo a phase transition at 110, 100 and 164 K, respectively. The transitions are reasonably attributed to orientational ordering of Cd-4 tetrahedra located at the center of icosahedral clusters; above the transition temperature the Cd-4 tetrahedra are completely disordered resulting in a bcc structure (Im (3) over bar), whereas below the temperature they are ordered in a non-cubic structure of a doubled unit cell, i.e. 2a x 2a x 2a or 2a x 2a x a superlattice. (C) 2004 Elsevier B.V. All rights reserved.