Formation of silver chromium spinels and structure determination of ferromagnetic AgCr2Te4

Abstract The silver chromium chalcogen spinel AgCr2Te4 has been prepared via ion exchange of the corresponding known copper chalcogen spinel CuCr2Te4 in aprotic Ag+ electrolyte. Electrochemical intercalation of Ag+ into AgCr2Te4 resulted in the formation of Ag1+yCr2Te4 with 0≦y≦1 , while ion exchange of Cu2Cr2Te4 with Ag+ electrolyte yielded directly the end member Ag2Cr2Te4 of the non-stoichiometric system. The structure of AgCr2Te4 was determined from X-ray powder data. The ferromagnetic properties of these new phases are discussed in terms of the concentration of anion p-band holes.