Spin dynamics in the high-T-c superconductor La2-x-ySrxREyCuO4

We performed inelastic magnetic neutron scattering experiments on the high- T-c superconductor La2-x-ySrxREyCuO4 with RE = Dy (x = 0, 0.25 and y = 0.09 ) and RE = Nd (x = 0. 0.12, 0.15, 0.2 and y = 0.1, 0.3). In this system an additional low temperature phase transition occurs, which has a strong impa ct on many physical properties. In particular the suppression of supercondu ctivity around the Sr-concentration of x = 1/8 is of interest. We investiga ted the magnetic behavior of the RE-moments in order to obtain information about the Cu magnetism in the CuO2-layers. The magnetic response shows qual itative differences at low temperatures which correlate with the electronic properties of the samples. The results are discussed with respect to the s tatic stripe model of spins and holes. (C) 1998 Elsevier Science Ltd. All r ights reserved.