Formation of core/shell structured cobalt/carbon nanoparticles by pulsed laser ablation in toluene

Abstract

Magnetic cobalt nanoparticles encapsulated in shells of layered structure have been produced by the technique of pulsed laser ablation in toluene. The morphology, microstructure, and magnetic properties of the prepared nanoparticles were characterized by electron microscopy, micro-Raman spectroscopy, and superconducting quantum interference device magnetometry, respectively. The results indicated that the cobalt nanoparticles fabricated are noncrystalline but coated with the graphitic carbon layers. It is believed that the formation of these carbon layers well-protect the cobalt nanoparticles to be oxidized thus maintaining the superparamagnetic property. This is an important feature that makes the cobalt nanoparticles a useful material for medical and many other magnetic based applications.

Synthesis of Magnetic Nanoparticles by Ultrashort Pulsed Laser Ablation of Iron in Different Liquids

“…[48] The fact that with differentp ulsed urationst he composition does not change is in accordance with investigationso nF e-Au alloy NPs by Wagener et al [42] showingt hat the pulse duration did not change the composition of the Fe-Aua lloys. Thus,f or liquidsw ith ah igh carbon content in the molecule not all of the carbon is incorporated into the NPs.…”

Nickel nanoparticles generated by pulsed laser ablation in liquid CO2

“…The active carbon atoms polymerize to form carbon layers surrounding the nickel nanoparticle core. The core/shell structure also resulted from PLA in liquid toluene with a cobalt target [39]. In addition, the formation of core/shell nanoparticles using metals such as gold, silver, and iron oxide have been reported [40,41].…”

“…When the temperature and pressure of the plasma plume decrease, the metal vapor ions condense rapidly to form nickel particles. Similar to the laser ablation of toluene [39], the breakdown of liquid CO 2 in the vicinity of the target may occur simultaneously, which produces highly active carbon atoms as well as carbon chains. The active carbon atoms polymerize to form carbon layers surrounding the nickel nanoparticle core.…”

Macroscopic behavior and microscopic magnetic properties of nanocarbon

“…On the other hand, possible role of magnetic impurities in triggering the FM order still cannot be excluded unambiguously [1,2], although evidence of a π-electron ferromagnetism in metal-free carbon samples has been established [8,9]. Hence, investigations of carbon structures with metallic atoms, magnetic or not, which have been introduced in the material intentionally, is interesting question for clarification the role of such atoms in formation of the magnetic properties of the material, as well as for application purposes [7][8][9][10][11][12][13].…”