Two magnetically distinct environments in Cu-O planes in an underdoped High-Tc cuprate: La(2-x)Sr(x)CuO(4) seen via ^17O NMR

Using high magnetic fields (30T) we investigate the normal state of the underdoped superconductor La(1.885)Sr(0.115)CuO(4) using ^17O NMR. The high field ^17O NMR spectrum shows evidence for two distinct planar oxygen signals, ^17O(p1) and ^17O(p2). The Knight Shift of ^17O(p1) drops linearly with decreasing temperature to zero near 60K, twice the zero field TC. ^17O(p2) Knight Shift drops non-linearly to zero below 40K. The ^17O(p2) line broadens with decreasing temperature while ^17O(p1) slightly narrows. Comparing the Knight Shift and linewidth of the two lines suggests very different magnetic environments.