X-ray absorption and x-ray magnetic dichroism study on Ca3CoRhO6 and Ca3FeRhO6

Abstract

Using x-ray absorption spectroscopy at the Rh-L2,3, Co-L2,3, and Fe-L2,3 edges, we find a valence state of Co 2+ /Rh 4+ in Ca3CoRhO6 and of Fe 3+ /Rh 3+ in Ca3FeRhO6. X-ray magnetic circular dichroism spectroscopy at the Co-L2,3 edge of Ca3CoRhO6 reveals a giant orbital moment of about 1.7µB , which can be attributed to the occupation of the minority-spin d0d2 orbital state of the highspin Co 2+ (3d 7 ) ions in trigonal prismatic coordination. This active role of the spin-orbit coupling explains the strong magnetocrystalline anisotropy and Ising-like magnetism of Ca3CoRhO6.