Hard magnetic properties of (001) oriented L1₀-FePd nanoparticles formed at 773 K

Two-dimensionally dispersed 10 nm-sized Fe/Pd and Fe/Pt particles (nanoparticles) with orientations have been fabricated with the same condition using an electron-beam evaporation technique. Heat treatments at temperatures above 773 K lead to a formation of L1₀-type (CuAu I-type) FePd and FePt ordered alloy particles with sizes as small as 10 nm. In the case of FePt nanoparticles, coercivity started to increase at 873 K, while in the case of FePd at 773 K. Moreover, in most of the FePd nanoparticles, their c-axes oriented normal to the film plane and the perpendicular coercivity reached as high as 1.2 kOe after annealing at 773 K for 1 h. This method can be applied to fabricate ultra-high density magneto-optical or vertical recording media under low annealing temperatures for the L1₀-structure formation especially in the Fe-Pd system.