Synthesis and characterization of the new delafossite-type oxide CuNi_(1/3)V_(2/3)O_2

摘要

Whereas neither delafossite-type Cu~I V~(III)O_2 nor Cu~I Ni~(III)O_2 exist,the authors have succeeded in preparing the delafossite oxide Cu~INi~(II)_(1/3)V~(IV)_(1/3)O_2,using classical solid-state reaction.The most probable formal oxidation state for nickel is II,while for vanadium it is a mixed state +III/+IV.The predominant magnetic interactions are antiferromagnetic,but no evidence could be found for long-range ordering.Charge transport results from a hopping process involving V~(3+)and V~(4+)cations.As XRD did not reveal any cation ordering,the observed T~(1/4)-dependence of the electrical conductivity(Mott's law)is ascribed to a random distribution of the relevant sites.