Indexed on: 01 Feb '96Published on: 01 Feb '96Published in: Czechoslovak Journal of Physics
The63Cu and17O NMR shift measurements in normal and superconducting states of Tl2Ba2Ca2Cu3O10−δ (TL2223) with various δ are reported. In the overdoped sample of Tl2223 with Tc<Tcopt and δ < δopt the different temperature dependencies of the Knight shift63,17K are revealed for nonequivalent CuO2 layers. A more gradual decrease of the shift with temperature takes place for inner CuO2 layer with the square oxygen coordination for Cu. In going towards the underdoped Tl2223 with Tc=104K and δ < δopt the changes of63,17K with temperature are found to be the same in different layers. Variations with doping of the valence contribution to electric field gradient at the Cu site are discussed to estimate the concentration of holes in different CuO2 layers.