Condensed-Matter Physics & Materials Science Seminar

The self-organization of doped holes on CuO2 planes has attracted much attention due to the connection with high-Tc superconductivity. It is believed that the static stripe formation of doped holes with segregating one-dimensional spin domains competes with the superconductivity, but the fluctuations are fundamental for the appearance of superconductivity. Here I present a result of systematic neutron-scattering experiments on La1.88-ySr0.12+yCu0.99R0.01O4 (y=0 for R=Cu, Zn and y=0.01 for R=Ga, Fe), which were performed with the aim to clarify the origin of stability of stripe order in cuprate oxides thought impurity-effect. The charge-density-wave (CDW) order was induced even in the low-temperature-orthorhombic (LTO) phase, which was thought to be inadequate for the stripe order, by impurity substitution regardless of the type of impurity. Besides, the stability was found to be enhanced significantly by Fe-doping than by Zn(Ga)-doping. Similar to the CDW order, the intensity of spin-density-wave (SDW) peak was markedly strengthened by Fe-doping, while the Zn- and Ga-doping effects on the intensity of SDW peak is negligible. These results indicate that the CDW order can be induced by the defect on CuO2 planes irrespective of the crystal structure, and that the stability of stripe order is effectively strengthened by magnetic impurity doping. I will discuss the universality of stripe correlation in cuprate oxides with showing the doping and energy dependences of SDW correlation in Fe-doped La2-xSrxCuO4.