title: Pressure-induced phase transitions in the Cd-Yb periodic approximant to a quasicrystal.
abstract: The phase study of a Cd-Yb 1/1 approximant crystal over a wide pressure and temperature range is crucial for the comparison study between periodic and quasiperiodic crystals. The Cd(4) tetrahedra, the most inner part of the atomic clusters, exhibited various structural ordering in the orientation sensitive to pressure and temperature. Five ordered phases appeared in a P-T span up to 5.2 GPa and down to 10 K. The propagation direction of ordering alternated from [110] to <111> to at about 1.0 GPa and again to [110] at 3.5-4.3 GPa. The primarily ordered phases that appeared by cooling to 210-250 K between 1.0-5.2 GPa further transformed to finely ordered ones at 120-155 K. Besides the original short-range type interaction, a long-range type interaction was likely developed under pressure to lead to the primary ordering of Cd(4) tetrahedra. Coexistence of these interactions is responsible for the complicated phase behavior.
authors.affiliation: Synchrotron Radiation Research Center, Japan Atomic Energy Agency, Mikazuki, Hyogo 679-5148, Japan. wata@spring8.or.jp
authors.forename: Tetsu
authors.initials: T
authors.lastname: Watanuki
authors.forename: Akihiko
authors.initials: A
authors.lastname: Machida
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ikeda
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Aoki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kaneko
authors.forename: Takahisa
authors.initials: T
authors.lastname: Shobu
authors.forename: Taku J
authors.initials: TJ
authors.lastname: Sato
authors.forename: An Pang
authors.initials: AP
authors.lastname: Tsai