Reduced interfacial magnetic moment of Y3Fe5O12 by capping Pt

The proximity effects of the Pt layers on the magnetic properties of the ultrathin Y3Fe5O12 (YIG) films have been systematically investigated. A significant decrease in the saturation magnetization is observed after capping the Pt films on the YIG films, indicating that a strong interaction occurs between Pt and YIG. In contrast, the magnetic properties remain essentially unchanged for YIG capping with the Cu films. The X-ray magnetic circular dichroism measurements show that a selective charge transfer occurs from Pt to the tetrahedral site Fe of YIG, leading to a reduction of the magnetic moment of the interfacial YIG. Our findings provide important clues to further understanding the pure spin current transport at the Pt/YIG interface.