Magnetic properties of copper chalcogenide spinels

Following the discovery of a charge-density wave in the cubic chalcogenide spinel Cu${\mathrm{V}}_2$ ${\mathrm{S}}_4$, the other known copper chalcogenide spinels were synthesized and their magnetic susceptibility measured to look for similar phase transitions. No phase transitions were observed in these other compounds. The present data also show that the electrons in metallic Cu${\mathrm{V}}_2$ ${\mathrm{S}}_4$ are highly correlated (the magnetic susceptibility is greatly enhanced). Data concerning the effects of alloying and nonstoichiometry on the magnetic properties of Cu${\mathrm{V}}_2$ ${\mathrm{S}}_4$ are also presented.