Abstract
We investigated the effect of spin dilution on the structural and magnetic properties of delafossite CuCrO2 having an S=3/2 antiferromagnetic triangular lattice (ATL) by the substitution of Ga3+ for Cr3+ by measurements of magnetization. Spin defects introduced into Cr ATL layers blur the antiferromagnetic transition and induce a dimensional crossover of low-energy magnetic excitation in the residual Cr ATL region due to the reduction of inter-layer magnetic interaction, while accompanying an enhancement of a spin-glass component.