Coercivity Control of FePt Nanoparticles by Interfacial Disorder

Abstract

Thin disordered layer can be formed by sputter-deposition of alumina on fully ordered L1 0 FePt nanoparticle assembly, due to plasma damage. The thickness of the disordered layer can be tuned by the sputtering power and deposition time of the alumina target. This partial disordering causes substantial decrease in the coercivity, which may be effective to adjust very high switching field of L1 0 FePt to practical magnetic recording systems.

Magnetization reversal of FePt hard/soft stacked nanocomposite particle assembly

“…The in-plane TEM image shows that the particles are isolated from each other. 7 Figure 4 shows the change in the thickness of the Figure 5 shows magnetization curves of the FePt films ͑a͒ with 0 nm, ͑b͒ 0.1 nm, ͑c͒ 0.3 nm, and ͑d͒ 0.7 nm thick a-Al 2 O 3 overlayers. The cross-sectional bright-field TEM image shows that the height of the particles is about 5 nm.…”

“…6,7 Since K u of the disordered FePt phase is one or two orders of magnitude smaller than that of the L1 0 phase, the assembly of interfacially disordered FePt particles is equivalent to the hard/soft stacked medium. 6,7 Since K u of the disordered FePt phase is one or two orders of magnitude smaller than that of the L1 0 phase, the assembly of interfacially disordered FePt particles is equivalent to the hard/soft stacked medium.…”