Competition between Charge- and Spin-Density-Wave Order and Superconductivity in La1.875Ba0.125-xSrxCuO4
We have performed a series of elastic neutron scattering measurements on 1/8-hole doped La1.875-Ba0.125-xSrxCuO4 single crystals with x = 0.05, 0.06, 0.075, and 0.085. Both charge-density-wave (CDW) and spin-density-wave orders are found to develop simultaneously below the structural transition temperature between the low-temperature orthorhombic (LTO) and low-temperature tetragonal (LTT) or low-temperature less-orthorhombic (LTLO) phases. In the ground state the CDW order is observed only in the LTT/LTLO phase and drastically degrades towards the LTO boundary. The x dependence of Tc strongly suggests a direct effect of the CDW order on the suppression of superconductivity.