TY - JOUR
T1 - Crystal structure analysis of Co-based layered cuprates CoSr2(Y1-xCax)Cu2O7+δ by transmission electron microscopy techniques
AU - Nagai, T.
AU - Baba, Y.
AU - Karppinen, M.
AU - Asaka, T.
AU - Alam, S.
AU - Yamauchi, H.
AU - Yamazaki, A.
AU - Kimoto, K.
AU - Matsui, Y.
N1 - Funding Information:
The authors are grateful to C. Tsuruta for helpful discussion and technical assistance with the present experiments. This work was supported by the Nanotechnology Support Project of the MEXT, Japan and also by a Grant-in-aid for Scientific Research (No. 15206002) from the Japan Society for the Promotion of Science and by Academy of Finland (Decision No. 116254).
PY - 2007/12/1
Y1 - 2007/12/1
N2 - Crystal structures of Co-based 1212-type layered cuprates, CoSr2(Y1-xCax)Cu2O7+δ (x = 0, 0.4; δ = 0, 0.3) have been investigated by means of transmission electron microscopy (TEM). For the non-superconductive CoSr2YCu2O7.0 parent phase (x = 0, δ = 0), electron diffraction (ED) patterns revealed superlattice reflections due to an ordered arrangement of two kinds of chain of CoO4 tetrahedra that are mirror images of each other, along the b direction. In the non-superconductive CoSr2(Y0.6Ca0.4)Cu2O7.0 phase (x = 0.4, δ = 0), the superlattice reflections were found to be streaked along the b* direction, indicating that the partially disordered arrangement is induced by aliovalent CaII-for-YIII substitution. In the superconductive CoSr2(Y0.6Ca0.4)Cu2O7.3 phase (x = 0.4, δ = 0.3), the superlattice reflections are not seen anymore, suggesting that the distinction of the two CoO4 chains has disappeared. Furthermore, high-resolution TEM observation revealed that the introduced excess oxygen atoms interrupt the regular shift of the chain position along the c direction.
AB - Crystal structures of Co-based 1212-type layered cuprates, CoSr2(Y1-xCax)Cu2O7+δ (x = 0, 0.4; δ = 0, 0.3) have been investigated by means of transmission electron microscopy (TEM). For the non-superconductive CoSr2YCu2O7.0 parent phase (x = 0, δ = 0), electron diffraction (ED) patterns revealed superlattice reflections due to an ordered arrangement of two kinds of chain of CoO4 tetrahedra that are mirror images of each other, along the b direction. In the non-superconductive CoSr2(Y0.6Ca0.4)Cu2O7.0 phase (x = 0.4, δ = 0), the superlattice reflections were found to be streaked along the b* direction, indicating that the partially disordered arrangement is induced by aliovalent CaII-for-YIII substitution. In the superconductive CoSr2(Y0.6Ca0.4)Cu2O7.3 phase (x = 0.4, δ = 0.3), the superlattice reflections are not seen anymore, suggesting that the distinction of the two CoO4 chains has disappeared. Furthermore, high-resolution TEM observation revealed that the introduced excess oxygen atoms interrupt the regular shift of the chain position along the c direction.
KW - Co-based cuprates
KW - Crystal structure
KW - Superconductor
KW - Transmission electron microscopy
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U2 - 10.1016/j.physc.2007.10.012
DO - 10.1016/j.physc.2007.10.012
M3 - Article
AN - SCOPUS:36148931722
SN - 0921-4534
VL - 467
SP - 192
EP - 197
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
IS - 1-2
ER -