Approach to enhance the coercivity in perpendicular FePt/Ag nanoparticle film

[FePt 2 nm/Ag d nm](10) multilayers were prepared on 100 degrees C MgO (100) single-crystal substrates with magnetron sputtering. The ordering and perpendicular texture of L1(0)-FePt/Ag particle films with high coercive force were realized at a lower postannealing temperature and by controlling accurately the atomic ratio of Fe to Pt of L1(0)-FePt films. The results of the x-ray-diffraction pattern show that the FePt particles have excellent (001) texture when the multilayers were sputtered on 100 degrees C substrates with the thickness of the Ag layer d=3-9 nm, and the mean size of L1(0)-FePt particles reduces with increasing thickness of the Ag layer. After the [FePt 2 nm/Ag 5 nm](10) was vacuum annealed at 600 degrees C for 15 min, the mean size of L1(0)-FePt particles is roughly about 8 nm and its perpendicular coercive force reaches 979 kA/m(12.3 kOe). This particle film has little magnetic exchange coupling and is a candidate for future perpendicular magnetic recording media with ultrahigh density.