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LiV2O4



LiV2O4 gained considerable interest after reports of heavy-fermion (HF) formation at low temperatures. In the literature, based on heat capacity, NMR spin-lattice relaxation and neutron scattering results, this compound was treated as a d-based HF system, an interpretation which has been corroborated by band structure calculations.

 

LiV2O4 crystallizes in the fcc normal spinel structure and is characterized by vanadium ions in a d1/d2 mixed valence state. Band structure calculations revealed that the t2g level close to the Fermi energy is separated into lower A1g and higher Eg orbitals, where the former are occupied by localized electrons (d1, S = 1/2) and the latter orbitals (d0.5) constitute the band states of itinerant electrons. Due to this scenario of localized and itinerant electrons, the HF formation was put down to the Kondo-effect where the magnetic moments of the localized electrons at low temperatures are fully compensated by clouds of itinerant electrons.


We measured the NMR spin-lattice relaxation rate 1/T1 of the 7Li nuclei in LiV2O4 at low temperatures (T < 1K) and observed the slowing down of uncompensated magnetic moments. Therefore it is questionable whether the Kondo-effect provides the only appropriate mechanism for the HF formation in LiV2O4.

 LiV2O4

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For further information contact: norbert.buettgen@physik.uni-augsburg.de