Transformation to L10 structure in FePd nanoparticles synthesized by modified polyol process

FePd nanoparticles were prepared by the modified polyol process, i.e. simultaneous reduction of palladium acetylacetonate and thermal decomposition of iron pentacarbonyl in a solvent. The well-dispersed FePd particles, with the average particle size of similar to 8.4 nm, were obtained using diphenyl ether as a solvent. The structure of FePd nanoparticles transformed to L1(0) structure from face centered cubic (fee) structure after annealing at 600 degrees C for 1 h in vacuum. The coercivity of the ordered FePd nanoparticles increased to similar to 2 kOe at 5 K from similar to 0.6 kOe in the fcc as-made FePd nanoparticle. On the other hand, FePd nanoparticles, synthesized based on the conventional modified polyol process using dioctyl ether as a solvent, showed no structural transformation after annealing up to 700 degrees C. This is explained in terms of the interruption of thermal diffusion of Fe and Pd atoms during the thermal treatment due to the mixture of interstitial carbon impurity in the synthesis process using dioctyl ether as a solvent. (c) 2006 Elsevier Ltd. All rights reserved.