Oriented self-assembly of cubic FePt nanoparticles

Chemically synthesized FePt nanoparticles have potential for application as magnetic media for data storage. In order to be used as data storage media, however, they must be deposited on substrates in such a way that their magnetic axes are aligned with respect to one another and with respect to the substrate, a problem that has yet to be overcome with spherical FePt nanoparticles. In this work we report the initial results of efforts to synthesize single crystalline FePt nanoparticles with cubic shapes. Our synthesis yields particles with shapes that are close to cubic or rectangular. When deposited on surfaces these particles assemble with local order and a square lattice. More importantly, they orient themselves with their [100] axes perpendicular to the surface and with local interparticle alignment of the [010] and [001] axes oriented parallel to the surface. These films of FePt nanocubes begin to overcome several of the obstacles associated with the development of magnetic data storage media based on self-oriented magnetic arrays of FePt nanoparticles.