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Comment on "Spinless impurities in high- T(c) cuprates: Kondo-like behavior".

Physical Review Letters (Impact Factor: 7.94). 03/2002; 88(5):059701.
Source: PubMed

ABSTRACT The recent obervation of a Kondo-like temperature dependence in the Li
NMR Knight shift in Ca- and Li- cosubstituted YBa2Cu3O7-d was attributed
by Bobroff et al. to be evidence of Li-induced local moments in
overdoped Y123. It is shown from Y-NMR measurements on
Y0.8Ca0.2Ba2Cu3O7-d and heat capacity studies on Bi2Sr2CaCu2O8 that such
a Kondo-like temperature dependence is an intrinsic overdoping effect
quite generally present in cuprate superconductors which are free of
strong scatterers such as Zn and Li. It is probable that Zn and Li only
induce local moments in the underdoped pseudogap region and not in the
overdoped region.

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