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Synthesis of magnetic nanofibers using femtosecond laser material processing in air.

Alubaidy MA, Venkatakrishnan K, Tan B - Nanoscale Res Lett (2011)

Bottom Line: The nanofibers diameter varies between 30 and 70 nm and they are mixed with nanoparticles.X-ray diffraction (XRD) analysis revealed metallic and oxide phases in the nanostructure.The growth of magnetic nanostructure is highly recommended for the applications of magnetic devices like biosensors and the results suggest that the pulsed-laser method is a promising technique for growing nanocrystalline magnetic nanofibers and nanoparticles for biomedical applications.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, M3N 2H8, Canada. venkat@ryerson.ca.

ABSTRACT
In this study, we report formation of weblike fibrous nanostructure and nanoparticles of magnetic neodymium-iron-boron (NdFeB) via femtosecond laser radiation at MHz pulse repetition frequency in air at atmospheric pressure. Scanning electron microscopy (SEM) analysis revealed that the nanostructure is formed due to aggregation of polycrystalline nanoparticles of the respective constituent materials. The nanofibers diameter varies between 30 and 70 nm and they are mixed with nanoparticles. The effect of pulse to pulse separation rate on the size of the magnetic fibrous structure and the magnetic strength was reported. X-ray diffraction (XRD) analysis revealed metallic and oxide phases in the nanostructure. The growth of magnetic nanostructure is highly recommended for the applications of magnetic devices like biosensors and the results suggest that the pulsed-laser method is a promising technique for growing nanocrystalline magnetic nanofibers and nanoparticles for biomedical applications.

No MeSH data available.


Related in: MedlinePlus

Magnetic strength M as a function of laser pulse repetition rate.
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Figure 9: Magnetic strength M as a function of laser pulse repetition rate.

Mentions: Figure 9 shows the typical variations of magnetic strength M as a function of laser repetition rate for the NdFeB nanofibers grown at room temperature. The thickness of the generated fibers layer in all of the four pieces were the same [23], however, the morphology of the nanostructures would be changed because of the change in nanofibers size caused by the change in repetition rate. The data were for the samples measured with a Guassmeter along the in-plane direction. The figure indicates that at higher repetition rates, the M of the nanofibrous structure get lower due to the presence of an abundant amorphous phase which also shows lower coercivity. The relatively large coercivities of nanofibrous structures were due primarily to their specific morphology. Theory has predicted that a system containing magnetic dipoles that are arranged into a linear chain will exhibit an increase in coercivity [33]. Our results seemed to be consistent with this prediction as long as dipole-dipole interactions between grains played the dominant role in the magnetization process. The NdFeB grains contained in each nanofiber were actually aligned along its long axis, and the dipole-dipole interactions between grains tended to line up all magnetic dipoles along the same axis.


Synthesis of magnetic nanofibers using femtosecond laser material processing in air.

Alubaidy MA, Venkatakrishnan K, Tan B - Nanoscale Res Lett (2011)

Magnetic strength M as a function of laser pulse repetition rate.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211468&req=5

Figure 9: Magnetic strength M as a function of laser pulse repetition rate.
Mentions: Figure 9 shows the typical variations of magnetic strength M as a function of laser repetition rate for the NdFeB nanofibers grown at room temperature. The thickness of the generated fibers layer in all of the four pieces were the same [23], however, the morphology of the nanostructures would be changed because of the change in nanofibers size caused by the change in repetition rate. The data were for the samples measured with a Guassmeter along the in-plane direction. The figure indicates that at higher repetition rates, the M of the nanofibrous structure get lower due to the presence of an abundant amorphous phase which also shows lower coercivity. The relatively large coercivities of nanofibrous structures were due primarily to their specific morphology. Theory has predicted that a system containing magnetic dipoles that are arranged into a linear chain will exhibit an increase in coercivity [33]. Our results seemed to be consistent with this prediction as long as dipole-dipole interactions between grains played the dominant role in the magnetization process. The NdFeB grains contained in each nanofiber were actually aligned along its long axis, and the dipole-dipole interactions between grains tended to line up all magnetic dipoles along the same axis.

Bottom Line: The nanofibers diameter varies between 30 and 70 nm and they are mixed with nanoparticles.X-ray diffraction (XRD) analysis revealed metallic and oxide phases in the nanostructure.The growth of magnetic nanostructure is highly recommended for the applications of magnetic devices like biosensors and the results suggest that the pulsed-laser method is a promising technique for growing nanocrystalline magnetic nanofibers and nanoparticles for biomedical applications.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, M3N 2H8, Canada. venkat@ryerson.ca.

ABSTRACT
In this study, we report formation of weblike fibrous nanostructure and nanoparticles of magnetic neodymium-iron-boron (NdFeB) via femtosecond laser radiation at MHz pulse repetition frequency in air at atmospheric pressure. Scanning electron microscopy (SEM) analysis revealed that the nanostructure is formed due to aggregation of polycrystalline nanoparticles of the respective constituent materials. The nanofibers diameter varies between 30 and 70 nm and they are mixed with nanoparticles. The effect of pulse to pulse separation rate on the size of the magnetic fibrous structure and the magnetic strength was reported. X-ray diffraction (XRD) analysis revealed metallic and oxide phases in the nanostructure. The growth of magnetic nanostructure is highly recommended for the applications of magnetic devices like biosensors and the results suggest that the pulsed-laser method is a promising technique for growing nanocrystalline magnetic nanofibers and nanoparticles for biomedical applications.

No MeSH data available.


Related in: MedlinePlus