Magnetic Properties and Microstructure of Exchange Coupled ${\rm Fe}/({\rm FePt-Ag}_{2}{\rm Se})$ Particulate Films

Multilayers Ag/[Ag₂Se(0.1 nm)/FePt(1 nm)]₁₀ were alternately deposited on a glass substrate and subsequently annealed by rapid thermal process (RTP) at 800°C for 3 minutes. After RTP, the interface between FePt and Ag₂Se was intermixed to form the particulate films. The grains size of the L1₀ FePt decreased from 9.8 nm to 7.7 nm when the total thickness of Ag₂Se intermediate layer increases to 1 nm. The Fe layers with thickness of 1 nm, 3 nm, 5 nm were deposited on FePt-Ag₂Se particulate films at room temperature. The Fe/(FePt-Ag₂Se) particulate film shows perpendicular magnetization. The magnetization was increased and coercivity was decreased with Fe layer thickness. When the Fe layer thickness increased up to 5nm, two-steps in-plane magnetization curve was found. The magnetization reversal was occurred by the domain wall nucleation and propagation from Fe layer into FePt-Ag₂Se layer.