Nature of the magnetic stripes in fully oxygenated La2CuO 4 y

We present triple axis neutron scattering studies of static and dynamic magnetic stripes in an optimally oxygen doped cuprate superconductor, La2CuO4 y, which exhibits a clean superconducting transition at Tc 42K. Polarization analysis reveals that the magnetic stripe structure is equally represented along both of the tetragonal crystal axes and that the fluctuating stripes display significant weight for in plane as well as out of plane spin components. Both static magnetic order as well as low energy fluctuations are fully developed in zero applied magnetic field and the low energy spin fluctuations at amp; 8463; amp; 969; 0.3 10meV intensify on cooling. We interpret this as an indication that superconductivity and low energy spin fluctuations coexist microscopically in spatial regions which are separated from domains with static magnetic orde