Spin dynamics in charge doped antiferromagnets: A7Li NMR study in Ni1-x Li x O
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Summary
The effects of heterovalent substitutions causing itinerant holes in strongly correlated3d electron systems are studied by means of7Li NMR in lithium-doped antiferromagnetic NiO. The spin-lattice relaxation rates, driven by the fluctuation of Ni2+ (S = 1) ions, in the temperature range 10 K <T< 700 K and in external magnetic fields varying from 1T up to 9.4T, are used to obtain insights on the hole hopping and on their localization. The gaps between itinerant and localized states and their dependence on the doping are thus derived. Furthermore, below the charge localization temperature, the slowing-down of the spin excitations related to the freezing of effective anomalous magnetic moments induced on the antiferromagnetic matrix are investigated. A comparison with the corresponding situation in charge doped La2CuO4 is briefly addressed.
PACS 76.60.Es
Relaxation effectsPACS 01.30.Cc
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