相変化記録材料GeTe-Sb₂Te₃擬二元系化合物の結晶構造

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Crystal structures of the phase-change recording material, GeTe-Sb₂Te₃, pseudo-binary compounds have been investigated over a decade using synchrotron radiation and the large Debye-Scherrer camera installed at SPring-8’s BL02B2 beamline. These compounds can be crystallized into metastable single phase with NaCl-type structure, for instance, by instantaneous laser irradiation; however, they are transformed into stable phases with long period trigonal structures characterized by the chemical formula, (GeTe)_n(Sb₂Te₃)_{m (n, m; integer) after sufficient heat treatments. These stable phases can be described as structure with cubic close-packing periodicity (…ABCABC…) where the stacking rules of the Ge/Sb and Te layers are different from each other.}