Neutron scattering study of magnetic excitations in overdoped LaSrCuO

Wakimoto, Shuichi  ; Yamada, Kazuyoshi*; Tranquada, J. M.*; Frost, C. D.*; Birgeneau, R. J.*; Zhang, H.*

Neutron scattering experiments have been performed on the overdoped LaSrCuO (). Low energy magnetic excitations ( meV) show incommensurate peaks for the superconducting samples with a maximum at meV in the energy spectrum. As doping increases, the maximum of the dynamic susceptibility decreases linearly with and, finally, the low energy excitations become unobservable at coincidentally with the disappearance of bulk superconductivity. Time-of-flight measurements revealed that magnetic excitations for are markedly suppressed in the intermediate energy range ( meV), which is apparently consistent with a microscopic phase separation into a superconducting region which retains the antiferromagnetic correlations and a Fermi liquid region which has no magnetic correlations.