TY - JOUR
T1 - Modulated structure of misfit-layered compound [Bi2.08Sr 1.67Oy]0.54[CoO2]
AU - Yubuta, Kunio
AU - Begum, Shahnaz
AU - Ono, Yasuhiro
AU - Miyazaki, Yuzuru
AU - Kajitani, Tsuyoshi
PY - 2006/5/9
Y1 - 2006/5/9
N2 - The modulated structure of Bi2.49Sr2.00Co 2.22Ox is studied by electron diffraction analysis and high-resolution electron microscopy. The crystal structure consists of two interpenetrating subsystems of a CoO2 sheet and a distorted four-layered rock-salt-type (Bi,Sr)O block. Both subsystems have common a-axes, c-axes and β-angles with a = 4.99 Å, c = 15.25 A, and β = 93.6°. On the other hand, the crystal structure is incommensurately modulated parallel to the b-axis, in which b1 = 2.78 Å for the CoO2 sheet and b2 = 5.12 Å for the (Bi,Sr)O block, respectively. These vectors characterize the structural analogue as [Bi 2.08Sr1.67Oy]0.54[CoO2]. It is found that this compound has various modulation vectors, q1 = -a* + 0.54b1*, q2 = 0.05b1* and locally q3 = -0.14a* + 0.10b1*. The intrinsic modulation vector q2 is different from that in [Bi 0.87SrO2]2[CoO2]1.82 studied by Leligny et al. High-resolution images taken with the incident electron beam parallel to the a- and c-axes clearly exhibit modulated atomic arrangements. The local modulation mode characterized by the vector q 3 is associated with the shear deformation in the a-b plane.
AB - The modulated structure of Bi2.49Sr2.00Co 2.22Ox is studied by electron diffraction analysis and high-resolution electron microscopy. The crystal structure consists of two interpenetrating subsystems of a CoO2 sheet and a distorted four-layered rock-salt-type (Bi,Sr)O block. Both subsystems have common a-axes, c-axes and β-angles with a = 4.99 Å, c = 15.25 A, and β = 93.6°. On the other hand, the crystal structure is incommensurately modulated parallel to the b-axis, in which b1 = 2.78 Å for the CoO2 sheet and b2 = 5.12 Å for the (Bi,Sr)O block, respectively. These vectors characterize the structural analogue as [Bi 2.08Sr1.67Oy]0.54[CoO2]. It is found that this compound has various modulation vectors, q1 = -a* + 0.54b1*, q2 = 0.05b1* and locally q3 = -0.14a* + 0.10b1*. The intrinsic modulation vector q2 is different from that in [Bi 0.87SrO2]2[CoO2]1.82 studied by Leligny et al. High-resolution images taken with the incident electron beam parallel to the a- and c-axes clearly exhibit modulated atomic arrangements. The local modulation mode characterized by the vector q 3 is associated with the shear deformation in the a-b plane.
KW - Electron diffraction
KW - High-resolution image
KW - Misfit-layered structure
KW - Modulated structure
KW - Residual strain
KW - Shear deformation
KW - Thermoelectric compound
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U2 - 10.1143/JJAP.45.4159
DO - 10.1143/JJAP.45.4159
M3 - Article
AN - SCOPUS:33646893684
SN - 0021-4922
VL - 45
SP - 4159
EP - 4164
JO - Japanese Journal of Applied Physics
JF - Japanese Journal of Applied Physics
IS - 5 A
ER -