Direct observation of the Fe substitution effect on the MCD spectra of the dysprosium iron garnet family

Abstract

Soft x-ray magnetic circular dichroism (MCD) and absorption spectra (XAS) were measured at the Fe L2,3-edges and the Dy M4,5-edges for a family of dysprosium iron garnets. The Fe ions sit in either Oh symmetry sites or Td symmetry sites in Dy3Fe5O12. Only Fe ions in the Oh sites are substituted with In ions in Dy3Fe4.25In0.75O12 and only Fe ions in the Td sites are substituted with Ga ions in Dy3Fe4.25Ga0.75O12. The XAS spectrum profiles of the three-dysprosium iron garnets are very similar. The MCD signals of both the Fe L2,3-edges and the Dy M4,5-edges of Dy3Fe4.25Ga0.75O12 are similar to that of Dy3Fe5O12, but Dy3Fe4.25In0.75O12 is remarkably different. The results directly show that the spin moment of Fe in the Td sites play a major role in determining the total magnetization of Dy3Fe5O12.