2019 年 29 巻 4 号 p. 262-271
In this article, uniaxial compression effects on cuprate superconductors such as YBa2Cu4O8 [Y-124], Y0.98Ca0.02Ba2Cu4O8 [Y0.98Ca0.02-124], and Hg0.83Re0.18Ba2Ca2.4Cu3.6O14 [Hg0.83(Re0.18)-1223] were reviewed. The uniaxial compression effects were compared with the hydrostatic compression effects via measuring the Meissner signal of their single crystals in the setup of using a diamond anvil cell. In Y-124 and Y0.98Ca0.02-124, the disappearance of the Meissner signal depended on the style of compression, and the difference in the change in the superconducting transition temperature Tc against initial compression are discussed with the structural symmetry of the CuO5 pyramid. In Hg0.83(Re0.18)-1223, the mechanism of increasing Tc is discussed on the basis of the first principle calculation.