Advanced phase change medium of over 30 GB capacity for blue laser and high-NA objective lens

Yusu, Keiichiro; Ashida, Sumio; Nakamura, N.; Oomachi, Noritake; Morishita, Naoki; Ogawa, Akihito; Ichihara, Katsutaro

doi:10.1109/omods.2002.1028684

Cited by 3 publications

(2 citation statements)

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“…These compounds, which are called a homologous series, can be described as structures with cubic close-packing periodicity (ÁÁÁABCABCÁÁÁ), where the stacking rules of the Ge, Sb and Te layers differ from each other. In this GeTe-Sb 2 Te 3 pseudobinary system, it was found several years ago that the crystallization speed, namely the rewrite speed, can be improved when a proportion of Sb is replaced by Bi (Yusu et al, 2002). The GeTe-Bi 2 Te 3 pseudobinary compounds as well as the GeTe-Sb 2 Te 3 compounds form another homologous series in a thermal equilibrium state (Shelimova et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Structures of stable and metastable Ge₂Bi₂Te₅, an intermetallic compound in a GeTe–Bi₂Te₃ pseudobinary system

Matsunaga¹,

Kojima²,

Yamada³

et al. 2007

Acta Crystallogr B Struct Sci

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Ge(2)Bi(2)Te(5) in the GeTe-Bi(2)Te(3) pseudobinary system has two single-crystalline phases: a metastable phase with an NaCl-type structure and a stable phase with a nine-layer trigonal structure. In the metastable phase, the structure consists, in the hexagonal notation, of infinitely alternating stacks of Te and Ge/Bi layers at equal intervals along the c axis. On the other hand, in the stable phase those two layers are stacked alternately nine times to form an NaCl block. The blocks are then piled to construct a nine-layered trigonal structure with cubic close-packed stacking. Both ends of each block are covered with Te layers, contrary to the infinite alternation of Ge/Bi and Te layers in the structure of the metastable phase. The Ge/Bi layers in the metastable phase contain as much as 20 at. % vacancies; on the other hand, those in the stable phase are filled with atoms. These two crystalline phases in Ge(2)Bi(2)Te(5) have identical atomic configurations to the two corresponding phases found in Ge(2)Sb(2)Te(5).

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Section: Introductionmentioning

confidence: 99%

Structures of stable and metastable Ge₂Bi₂Te₅, an intermetallic compound in a GeTe–Bi₂Te₃ pseudobinary system

Matsunaga¹,

Kojima²,

Yamada³

et al. 2007

Acta Crystallogr B Struct Sci

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“…More recently, it has been found that this crystallization speed can be improved in the (Ge,Sn)Te-Sb 2 Te 3 pseudobinary compounds when a proportion of Ge is replaced by Sn 9) and in the GeTe-(Sb,Bi) 2 Te 3 compounds, when a proportion of Sb is replaced by Bi. 10) To clarify whether these structural features are commonly seen in materials suitable for phase-change optical disks, we investigate here the crystal structures of Ge(Sb 0:5 Bi 0:5 ) 2 Te 4 , Ge 7:1 Sb 76:4 Te 16:5 and Sb and their temperature dependences. We discuss herein the relationship between the structural characteristics of these materials and their capability for high-speed transformation from the amorphous to the crystal phase by comparing them with compounds that have been previously analyzed.…”

Section: Introductionmentioning

confidence: 99%

Crystallographic Studies on High-Speed Phase-Change Materials Used for Rewritable Optical Recording Disks

Matsunaga

Yamada

2004

Jpn. J. Appl. Phys.

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Optical recording disks, which exploit the reversible phase-change phenomenon between amorphous and crystal states of a material, are now in extensive use, particularly in videodisc recorders for home use. The most commonly used recording materials are GeTe-Sb 2 Te 3 pseudobinary compounds and Sb-Te binary compounds with a small quantity of added In, Ag, and/or Ge. These compounds, which have superior capabilities for holding data at room temperature for extended periods and high rewrite speeds, all tend to have structures in which one lattice site is occupied by two or more elements at random, and the lattices are all cubic or pseudocubic at the high temperatures at which recording and erasure are performed. In addition, with rising temperature, the amplitude of atomic thermal vibration increases exponentially. It is believed that these two characteristics of these materials that are suitable for phase-change optical disks, i.e., an isotropic structure and intense thermal vibration at high temperatures, play very important roles in the virtually instantaneous transformation from the amorphous to the crystal phase. We describe here the relationship between the structural features and the high-speed phasechange mechanism.

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30GB/Side rewritable optical disk for HDTV utilizing a blue laser diode

Watabe

Takehara

Kashihara

et al. 2003

IEEE Trans. Consumer Electron.

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Advanced phase change medium of over 30 GB capacity for blue laser and high-NA objective lens

Cited by 3 publications

References 1 publication

Structures of stable and metastable Ge₂Bi₂Te₅, an intermetallic compound in a GeTe–Bi₂Te₃ pseudobinary system

Structures of stable and metastable Ge₂Bi₂Te₅, an intermetallic compound in a GeTe–Bi₂Te₃ pseudobinary system

Crystallographic Studies on High-Speed Phase-Change Materials Used for Rewritable Optical Recording Disks

30GB/Side rewritable optical disk for HDTV utilizing a blue laser diode

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Advanced phase change medium of over 30 GB capacity for blue laser and high-NA objective lens

Cited by 3 publications

References 1 publication

Structures of stable and metastable Ge2Bi2Te5, an intermetallic compound in a GeTe–Bi2Te3 pseudobinary system

Structures of stable and metastable Ge2Bi2Te5, an intermetallic compound in a GeTe–Bi2Te3 pseudobinary system

Crystallographic Studies on High-Speed Phase-Change Materials Used for Rewritable Optical Recording Disks

30GB/Side rewritable optical disk for HDTV utilizing a blue laser diode

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Product

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Structures of stable and metastable Ge₂Bi₂Te₅, an intermetallic compound in a GeTe–Bi₂Te₃ pseudobinary system

Structures of stable and metastable Ge₂Bi₂Te₅, an intermetallic compound in a GeTe–Bi₂Te₃ pseudobinary system