Interplay between spin glass and heavy fermion behavior in the d-metal oxides Li1-xZnxV2O4

The magnetic relaxation rate of the d-metal oxide system Li1-xZnxV2O4 has b een measured on polycrystalline samples for x=0.05, 0.1, 0.2, and 0.3 by me ans of quasielastic neutron scattering. All investigated compounds display a quasielastic response of magnetic origin with a residual quasielastic lin e width of 8-15 K followed by a square-root temperature dependence. We argu e that the residual linewidth corresponds to the energy scale of antiferrom agnetic fluctuations. The main effect of Zn doping is to introduce disorder . This is reflected by the formation of a spin glass state with increasing freezing temperature upon increasing Zn concentration. However, the present data are inconsistent with a spin-glass state alone but give indications o f strong hybridization effects. Our present results may be interpreted on t he basis of recent band structure calculations.