title: 63Cu NQR evidence for spatial variation of hole concentration in La2-xSrxCuO4.
abstract: We report experimental evidence for the spatial variation of hole concentration x(hole) in the high T(c) superconductor La2-xSrxCuO4 ( 0.04 < or = x < or = 0.16) via 63Cu NQR using 63Cu isotope enriched samples. We demonstrate that the extent of the spatial variation of the local hole concentration Delta(x)hole is reflected on (63)1/T1 and deduce the temperature dependence. Delta(x)hole increases below 500-600 K, and reaches values as large as Delta(x)hole/x approximately 0.5 below approximately 150 K. We estimate the length scale of the spatial variation in x(hole) to be R(hole) greater, similar 3 nm from an analysis of the NQR spectrum.
authors.affiliation: Department of Physics and Center for Materials Science and Engineering, M.I.T., Cambridge, Massachusetts 02139, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Singer
authors.forename: A W
authors.initials: AW
authors.lastname: Hunt
authors.forename: T
authors.initials: T
authors.lastname: Imai