Dynamics of the local moment induced by nonmagnetic defects in cuprates
We present a study of the spin dynamics of magnetic defects induced by Li substitution of the plane Cu in the normal state of YBa2Cu3O6+x. The fluctuations of the coupled Cu magnetic moments in the vicinity of Li are probed by near-neighbor 89Y and 7Li NMR spin lattice relaxation. The data indicate that the magnetic perturbation fluctuates as a single entity with a correlation time tau which scales with the local static susceptibility. This behavior is reminiscent of the low T Kondo state of magnetic impurities in conventional metals. Surprisingly it extends well above the "Kondo" temperature for the underdoped pseudogapped case.
MacFarlane
WA
LPS, Universite Paris-Sud, UMR8502 CNRS, Batiment 510, 91405, Orsay Cedex, France.
Bobroff
J
Alloul
H
Mendels
P
Blanchard
N
Collin
G
Marucco
J