Tetrahedral-Site Copper in Chalcogenide Spinels

摘要

The ferromagnetism and metallic conductivity of the compounds Cu(Cr2)X4, where X = S, Se, or Te, have been interpreted in terms of collective 'd' electrons of t2g symmetry from Cu(2+) ions and localized d electrons of t2g symmetry at Cr(3+) ions. Lotgering and van Stapele have studied the compounds CuCrRhSe4, CuCrTiS4, and M1-xCu(Cr2)Se4, where M = Zn, Cd, or Hg. They have asserted that their results disprove this hypothesis and strongly support the existence of Cr(4+) ions in the presence of Cu(+) ions. It is shown that these assertions are incorrect. (Author)