As shown in the inset of Fig.57, the
saturated relaxation rate [] takes a
maximum at the optimum doping concentration. The increase of
in the Zn `under-doped' regime indicates a
creation of static moments upon doping, being consistent with the
suppression of
and the enhancement of
(Fig.53). The decrease of
in the Zn `over-doped' regime is partly
attributed to trivial dilution of moments due to the Zn substitutions;
even if the size of ordered moments doesn't change upon Zn doping, the
muon relaxation rate should decrease as
,simply because of the decrease in the number of spins. Still, the
experimental result suggests more pronounced decrease; the relaxation
rate decreased by
% [
] in the change of Zn concentration
%. This result suggests that the ordered moments
shrinks in the Zn over-doped regime.