Spin-glass behavior in Li 1 − x Zn x V 2 O 4

${\mathrm{LiV}}_{2}{\mathrm{O}}_{4}$ is a transition-metal based heavy fermion compound close to magnetic order. Mixed crystals of ${\mathrm{Li}}_{1\ensuremath{-}x}{\mathrm{Zn}}_{x}{\mathrm{V}}_{2}{\mathrm{O}}_{4},$ $0g~xg~0.3,$ were investigated by zero-field-cooled and field-cooled magnetization and by ac susceptibility measurements at different frequencies and applied external dc fields. The measurements indicate two characteristic temperatures, a freezing temperature ${T}_{f}$ which is almost independent of the applied field and a temperature ${T}_{\mathrm{irr}}$ where strong irreversibilities occur and which strongly decreases on increasing fields. Comparison is made to heavy fermion spin glasses.