Novel ultrasonic-assisted alignment of L10 FePt nanoparticles

Chemically ordered (L10) FePt nanoparticles were synthesized by a microemulsion technique and the ordered phase was obtained by heating a mixture of particles and lyophilized NaCl as the separating medium, avoiding coalescence. A chloroform suspension of L10 FePt nanoparticles was evaporated at room temperature, assisted by ultrasonic vibration, producing the arrangement of the particles on the substrate. Parallel lines and flower-like patterns were obtained, starting from a 4×10−3 M suspension and using higher dilutions, suggesting that the fast evaporation of chloroform allows the particles deposition on the substrate, following the propagation direction of the ultrasound waves and/or placement at a vibration node, depending on the concentration.