Fabrication and Magnetic Properties of Ag/FePt Thin Films

Abstract

The effects of Ag under layer on the micro structural and magnetic properties of the FePt films were investigated. It was found that the thickness of the Ag under layer is very important factor to induce the L1₀ ordered FePt (001) films with high perpendicular anisotropy. The chemical ordering increased with increasing Ag layer thickness, reached its maximum at 40 nm, and then slightly decreased with further increasing Ag thickness to 50 nm. Moreover, the initial magnetization curve and the scanning electrode microscopy (SEM) results showed that the magnetization reversal mechanism of the Ag/FePt films changed from nucleation mode to pinning mode/S-W rotation with increasing the Ag thickness. The increase of the chemical ordering and the change of magnetization reversal mechanism from nucleation mode to pinning mode/S-W rotation led to the increase in out-of-plane coercivity when Ag thickness increased from 0 to 40 nm. For the sample with 50 nm Ag layer, the decrease in out-of-plane coercivity could be attributed to the decrease in the chemical ordering.

Keywords:

• Ag underlayer
• FePt
• Microstructure