title: Structural transformation of Sb-based high-speed phase-change material.
abstract: The crystal structure of a phase-change recording material (the compound Ag(3.4)In(3.7)Sb(76.4)Te(16.5)) enclosed in a vacuum capillary tube was investigated at various temperatures in a heating process using a large Debye-Scherrer camera installed in BL02B2 at SPring-8. The amorphous phase of this material turns into a crystalline phase at around 416 K; this crystalline phase has an A7-type structure with atoms of Ag, In, Sb or Te randomly occupying the 6c site in the space group. This structure was maintained up to around 545 K as a single phase, although thermal expansion of the crystal lattice was observed. However, above this temperature, phase separation into AgInTe(2) and Sb-Te transpired. The first fragment, AgInTe(2), reliably maintained its crystal structure up to the melting temperature. On the other hand, the atomic configuration of the Sb-Te gradually varied with increasing temperature. This gradual structural transformation can be described as a continuous growth of the modulation period γ.
authors.affiliation: Device Solutions Center, R&D Division, Panasonic Corporation, 3-1-1 Yagumo-Nakamachi, Moriguchi, Osaka 570-8501, Japan. matsunaga.toshiyuki@jp.panasonic.com
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsunaga
authors.forename: Rie
authors.initials: R
authors.lastname: Kojima
authors.forename: Noboru
authors.initials: N
authors.lastname: Yamada
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kubota
authors.forename: Kouichi
authors.initials: K
authors.lastname: Kifune