Discrepancy of the magnetic behaviors and crystalline structure on the Co/FeMn and FeMn/Co interfaces with ultrathin Pt spacer

The exchange coupling at the ferromagnetic/antiferromagnetic (FM/AFM) interface is influenced by both the magnetic structure and the crystalline micro-structure. Co/FeMn/Co thin films with 0.4 nm Pt spacer layer inserted into the Co/FeMn and FeMn/Co interface respectively were deposited by means of magnetron sputtering. The two interfaces upon and beneath the FeMn layer show distinct behaviors before and after the Pt spacer inserted. There is a remarkable shrink of the interfacial uncompensated spins within the FeMn bottom interfacial monolayers, whereas a relaxation of the pinning strength of the FeMn interfacial spins along the out-of-plane direction occurs at the top interface. XRD analysis indicates the Pt layer upon the FeMn layer forms an fcc (002) texture, implying the magnetic discrepancy between the top and bottom FeMn interfaces has crystalline structural origins.