We have observed magnetic circular dichroism (MCD) in the soft X-ray absorp
tion spectra of the semiconducting ferromagnet CdCr2Se4 and the metallic fe
rromagnets CuCr2S4 and CuCr2Se4. The Cr 2p X-ray absorption and MCD spectra
show that the d-electron occupancies of the Cr atom in the Cu-based Cr sul
fide and selenide are not much different from that in the CdCr2Se4 in spite
of the different formal valencies, Cr3.5+ and Cr3+, respectively. The obse
rved Cu 2p MCD spectra show the existence of small magnetic moments on the
Cu sites which are aligned antiparallel to the Cr 3d moment in CuCr2S4 and
CuCr2Se4, consistent with band-structure calculation. (C) 2001 Elsevier Sci
ence B.V. All rights reserved.