NMR and $\mu $SR studies of Sc (S=0) doping effects in a spin-Peierls system TiOCl

TiOCl is a model one-dimensional S=1/2 chain system with an incommensurate phase below T$_{c}\sim $95K and a spin-Peierls ground state below T$_{c}$'$\sim $65K. We report a detailed NMR and $\mu $SR investigation of the local lattice and spin environment in undoped and Sc (S=0) doped Ti$_{1-x}$Sc$_{x}$OCl (x = 0, 0.01, and 0.03). Based on $^{35}$Cl NMR lineshape measurements, we show that all Ti$_{1-x}$Sc$_{x}$OCl samples exhibit signatures of short-range Peierls distortion starting from as high as T*$\sim $130K. Moreover, the NMR line splits into two peaks below T$_{c}\sim $95K, corresponding to two types of local lattice geometries. Only undoped TiOCl develops sharp double peaks below T$_{c}$'=65K. $\mu $SR measurements reveal no evidence for a magnetic long range order down to 2K, even for x=0.03. We will compare our results with x-ray scattering measurements (J.P. Clancy et al., this meeting) and doped CuGeO$_{3}$.