Assembly of FePt L1 nanoparticles grown on MgO(110) with self-organized groove structure

Abstract

We have fabricated an FePt nanoparticle assembly on a MgO(110) with a self-organized structure. Prior to FePt deposition, the MgO(110) substrate was annealed at 1273K in air to develop self-organized grooves running along the [11¯0] direction with average periodicity of 14.5nm. Subsequently a very thin FePt layer with nominal thickness of 1.5nm was sputtered onto the MgO substrate at 973K, resulting in FePt L10 nanoparticles with 2–4nm in diameter aligned along the grooves. Each FePt nanoparticle was a L10 single crystal with its c-axis tilting 45° or −45° from the substrate normal that corresponds to MgO [100] or [010]. The magnetic properties of the FePt nanoparticle assembly well reflected such c-axis distribution, and their switching behavior almost followed the Stoner-Wohlfarth model.