IR laser deposition: Co2Sm5 nanocrystals in amorphous Sm-Co phase and amorphous Sm-Co nanobodies in carbonaceous phase

Pulsed IR laser irradiation of SmCo5 alloy in vacuum and in adjacent dielectric breakdown (DB) of benzene has been examined as a tool for modifying phase and composition of this alloy and for suitability to serve as a laser deposition technique of Sm-Co nanoparticles and Sm-Co/C films. The composition of solid deposits was determined by FTIR, X-ray photoelectron and Raman spectroscopy and electron microscopy, and gas-phase chemical changes upon irradiation in gaseous benzene were analyzed by gas chromatography and FTIR and GC/MS spectroscopy. IR laser ablation in vacuum leads to deposition of amorphous Sm1.00Co2.1-2.2 films containing uniformly dispersed Co2Sm5 nanocrystals and to formation of residual Sm2Co17 target phase, both of which indicating disproportionation of SmCo5 and Sm-enrichment of ablated particles. IR laser ablation in benzene results in formation of ultrafine powders consisting in fully amorphous Sm1.00Co4.2-4.6 nanoparticles embedded in amorphous hydrogenated carbonaceous phase and is in keeping with minor structural changes in ablated SmCo5 particles. Both deposited materials are shown to differ in magnetic properties and the carbonaceous shell serves as a protection of Sm-Co nanobodies towards atmospheric oxidation. (C) 2011 Elsevier B.V. All rights reserved.