梯子型超伝導体Sr_<14-X>Ca_XCu_<24>O_<41>の結晶構造と高圧物性 Cyrstal Structure and Physical Properties in the Spin-Ladder Superconductor Sr_<14-X>Ca_XCu_<24>O_<41>
The spin ladder system Sr<SUB>14-x</SUB>Ca<SUB>x</SUB>Cu<SUB>24</SUB>O<SUB>41</SUB> is reviewed from the viewpoint of relations be-tween the crystal structure and superconductivity under high pressure. The compound is a composite crystal, which consists of CuO<SUB>2</SUB> 1-D chain and Cu<SUB>2</SUB>O<SUB>3</SUB> tow-leg ladder subsystems. As the interplay of the subsystems is increased with Ca substitution or pressurization, holes are removed from the 1-D chain to the ladder via locally formed apical oxygen bonds. Then, the superconductivity occurs owing to the hole doping into the ladder. The hole distribution, magnetic interaction, and electrical property of the normal state are also discussed in terms of the structural modulation.
日本結晶学会誌 41(4), 251-260, 1999-08-30
The Crystallographic Society of Japan