L1o FePt-Based Exchanged Coupled Composite Films

The synthesis and characterization of L1(o) FePt phase films with c-axis orientation in the perpendicular direction (001), on SiO2/Si(100) substrates by RF magnetron sputtering, are reported. A single-layer of 10 nm of equiatomic FePt co-sputtered films was replicated with intermittent in situ inner-layer annealing to produce 20-nm, 60-nm, 100-nm, and 140-nm-thick FePt films. The thickness dependence of the magnetic, structural, elemental analysis, and surface morphological properties of the FePt films has been investigated using VSM, XRD, EDX, and SEM respectively. For the 20-nm-thick FePt films, excellent magnetic properties with high values of out-ofplane coercivity (H-c = 20 kOe) and squareness (S = 0.98) are obtained. The XRD data confirm the formation of the highly anisotropic L1(o) FePt phase. The surface morphology of the 20-nm film shows sphere-like grains, which have their c-axis orientation in the out-of-plane direction. The magnetic properties of the 60-nm films reveal a significant reduction in the coercivity (H-c = 11 kOe), but their c-axis orientation is still oriented in the out-of-plane direction. The formation of the (111) plane of the soft-magnetic phase A(1)-FePt reduced the magnetic properties; however, the coercivity is reduced slightly. Films thicker than 60 nm exhibit a reduction in the ordering parameter S, which indicates a deterioration of the c-axis orientation in the out-of-plane direction; SEM data confirm the coalescence of the grains for films thicker than 100 nm.

Automated summary

The synthesis and characterization of L1(o) FePt phase films with c-axis orientation in the perpendicular direction on SiO2/Si(100) substrates by RF magnetron sputtering are reported. The magnetic, structural, elemental analysis, and surface morphological properties of FePt films of different thicknesses were investigated. Thinner films exhibited excellent magnetic properties, while thicker films showed a deterioration in c-axis orientation.