Spin dynamics and magnetic properties of overdoped LaSrCuO

Wakimoto, Shuichi  

Spin excitation has been studied by neutron scattering experiments for the overdoped LaSrCuO for . Incommensurate excitations have been observed for the superconducting samples for . Energy spectrum of dynamic susceptibility for those samples shows maximum at 6 meV and no spin-gap is observed down to 2 meV. Interestingly the maximum dynamic susceptibility decreases linearly with decreasing , and finally, the low energy excitation becomes unobservable at coincidentally with the disappearance of bulk superconductivity. This implies an intimate relationship between the superconductivity and the low energy spin excitation. Magnetization measurements of overdoped LSCO with and without Zn impurities have revealed that the superconductivity vanishes in the overdoped regime as a result of a competition between the superconductivity and paramagnetism which is induced even in the Zn-free overdoped LSCO. In this talk, we report details of these results together with results of recently measured high-energy magnetic excitations which show weakened magnetic correlations of the overdoped samples not only in the low energy region but also in the high energy region.