High field, low temperature 17O Knight shift in an underdoped High-Tc cuprate: La(2-x)Sr(x)CuO(4) for x =0.115, 0.15

We use high magnetic fields ($>$30T) to suppress the superconducting Tc in order to investigate the normal state NMR properties of La(2-x)Sr(x)CuO(4) (LSCO) at low temperatures. Recent studies have shown glassy behavior and incommensurate spin-waves in LSCO, which has been discussed as evidencing a stripe ordered picture at low temperatures in the under-doped regime. We use 17O NMR as a local probe of the electron density on the planar oxygens. 17O Knight shift and linewidth were obtained over a wide temperature range in the normal state for under-doped (x=0.115) and optimally doped (x=0.15) LSCO.