AN O-17 NMR-STUDY OF HG0.5TL0.5BA2(CA1-XSRX)2CU3O8+DELTA

We have obtained O-17 nuclear magnetic resonance spectra of magnetical ly aligned Hg0.5Tl0.5Ba2(Ca1-xSr(x))2Cu3O8+delta at 300 K. The princip al components of the electric-field gradient and the Knight-shift tens ors are obtained for all oxygen sites in this mercury-based triple Cu- O layered superconductor. The results show that both the EFG and Knigh t shift tensors of the inner CuO2 plane oxygens are considerably small er than those of the outer CuO2 plane oxygens, indicating a smaller sp in susceptibility and a reduced hole density in the inner CuO2 plane.