In situ magnetic field alignment of directly ordered L1 FePt nanoparticles

Gas-phase prepared directly ordered FePt nanoparticles were shown to align with in situ magnetic fields. As shown by magnetic and x-ray diffraction data, a 3800Oe perpendicular field switched L10 FePt particles with a mean size of 6nm from in-plane arrangement in as-deposited state to out-of-plane orientation. A 5000Oe in-plane field successfully defined nanoparticles with in-plane texture. These results demonstrated the feasibility of preparing nanoparticle-based magnetic recording media and exchange-spring-type permanent magnets with desired magnetic orientation control. Only involving thermal fluctuation as the obstacle, this approach makes an ideal subject for theoretical understanding and further optimization.