Neutron scattering studies of Zn-doped La2-xSrxCuO4

Abstract

This paper reviews studies of the spatial modulation of spin in La2-xSrxCuO4 (LSCO) through neutron-scattering measurements of the elastic magnetic peaks, with emphasis on Zn-doped LSCO. The elastic incommensurate magnetic peaks can be categorized in two classes with respect to the temperature dependence. Nd-doped LSCO, La2CuO4+y and LSCO with x ~ 1/8 exhibit an ordinary power law behavior. On the other hand, Zn-doped LSCO and LSCO with x = 0.02-0.07 show an exponential temperature dependence, and the correlation lengths stay short. This discrepancy can be attributed to the difference in the mechanism of pinning spin fluctuations. The former systems have pinning centers which is coherent to the lattice. In the latter, however, pinning centers are randomly scattered in the CuO2 planes, thus incoherent. The incoherent pinning model is discussed with referring to recent mu-SR studies.