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

Abstract

[ FePt 2 nm ∕ Ag d nm ] 10 multilayers were prepared on 100 °C MgO (100) single-crystal substrates with magnetron sputtering. The ordering and perpendicular texture of L10-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 L10-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 °C substrates with the thickness of the Ag layer d=3–9nm, and the mean size of L10-FePt particles reduces with increasing thickness of the Ag layer. After the [FePt2nm∕Ag5nm]10 was vacuum annealed at 600 °C for 15 min, the mean size of L10-FePt particles is roughly about 8 nm and its perpendicular coercive force reaches 979kA∕m(12.3kOe). This particle film has little magnetic exchange coupling and is a candidate for future perpendicular magnetic recording media with ultrahigh density.