Spin- and charge-density-wave orders in La1.87Sr0.13Cu0.99Fe0.01O4

We have performed elastic neutron-scattering measurements on La1.87Sr0.13Cu0.99Fe0.01O4 to study the magnetic impurity effects on the stripe correlations in high-Tc cuprates. Both charge-density-wave (CDW) and spin-density-wave (SDW) orders are observed in the low-temperature-orthorhombic (LTO) phase for the first time. With decreasing the temperature, CDW order first appears at ∼60K followed by the SDW order at lower temperature of ∼50K. The incommensurability for the CDW order (ε) was found to be 0.224±0.002 r.l.u., which is approximately twice of that for SDW order (δ) of 0.115±0.003 r.l.u. Both ordering sequence and relation of ε≈2δ are the same for SDW and CDW orders observed in the low-temperature-tetragonal (LTT) phase of La1.60-xNd0.4SrxCuO4 (LNSCO), suggesting that the similar stripe correlations exist in the cuprate oxides, irrespective of crystal structure.