Microscopic origin of ferrimagnetism of a double perovskite Sr₂FeMoO₆: An x-ray magnetic circular dichroism study

We have studied the microscopic magnetic state of a double perovskite Sr₂FeMoO₆ by x-ray magnetic circular dichroism (XMCD). An Fe L_3,2-edge XMCD reveals that the formal Fe³⁺ ions have an appreciable orbital moment (m_orb) parallel to their large spin moment (m_spin), showing the charge-transfer-induced, minority-spin (↓) Fe t_2g electrons. A weak but undoubted O K-edge XMCD was successfully detected, showing an O 2p-hole m_orb induced by 2p-3d hybridization. Along with information obtained from the observed Mo M_3,2-edge XMCD, our findings verify the partially filled Fe 3d t_2g↓-O 2p_π↓-Mo 4d t_2g↓ hybridized bands at the Fermi level, which mediates ferrimagnetism.