Influence of hydrogen on the Y89 NMR in HxYBa2Cu3O7

The ambient-temperature Y89 magnetic resonance line in HxYBa2Cu3O7 was measured at 14.707 MHz as a function of hydrogen concentration x. The Knight shift relative to an aqueous solution of YCl3 increases from -100 ppm for x=0 to +115 ppm for x=1.82. The linewidth at half-amplitude is 1.2 kHz and increases slowly with x in the superconducting samples (0<x<0.74), then increases sharply in the normal samples. It was seen that, for a number of parameters, increasing the hydrogen content gives similar behavior to decreasing the oxygen concentration. Our Y89 NMR data and those of other investigators are analyzed and are consistent with previous evidence for local antiferromagnetic correlations in the superconducting compound.