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Synthesis, magnetic and optical properties of core/shell Co1-xZnxFe2O4/SiO2 nanoparticles.

Girgis E, Wahsh MM, Othman AG, Bandhu L, Rao K - Nanoscale Res Lett (2011)

Bottom Line: It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases.On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles.These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications.

View Article: PubMed Central - HTML - PubMed

Affiliation: Solid State Physics Department, National Research Centre, 12311 Dokki, Giza, Egypt. egirgis@gmail.com.

ABSTRACT
The optical properties of multi-functionalized cobalt ferrite (CoFe2O4), cobalt zinc ferrite (Co0.5Zn0.5Fe2O4), and zinc ferrite (ZnFe2O4) nanoparticles have been enhanced by coating them with silica shell using a modified Stöber method. The ferrites nanoparticles were prepared by a modified citrate gel technique. These core/shell ferrites nanoparticles have been fired at temperatures: 400°C, 600°C and 800°C, respectively, for 2 h. The composition, phase, and morphology of the prepared core/shell ferrites nanoparticles were determined by X-ray diffraction and transmission electron microscopy, respectively. The diffuse reflectance and magnetic properties of the core/shell ferrites nanoparticles at room temperature were investigated using UV/VIS double-beam spectrophotometer and vibrating sample magnetometer, respectively. It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases. The cobalt ferrite nanoparticles fired at temperature 800°C; show the highest saturation magnetization while the zinc ferrite nanoparticles coated with silica shell shows the highest diffuse reflectance. On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles. These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications.

No MeSH data available.


Photographs of CoFe2O4/SiO2 (a), Co0.5Zn0.5Fe2O4/SiO2 (b), and ZnFe2O4/SiO2 (c) nanoparticles fired at 400°C.
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Figure 7: Photographs of CoFe2O4/SiO2 (a), Co0.5Zn0.5Fe2O4/SiO2 (b), and ZnFe2O4/SiO2 (c) nanoparticles fired at 400°C.

Mentions: Figure 7 shows the photographs of CoFe2O4/SiO2 (Figure 7a), Co0.5Zn0.5Fe2O4/SiO2 (Figure 7b), and ZnFe2O4/SiO2 (Figure 7c) core/shell ferrite nanoparticles fired at 400°C for 2 h, with and without an external magnet effect. It can be seen that all the core/shell nanoparticles show manifestations of ferromagnetic behavior as shown in the photographs where the nanoparticles were attracted to the external magnet. Also, it is clear that the nanoparticles colors were changed from black (CoFe2O4/SiO2), to brown (Co0.5Zn0.5Fe2O4/SiO2), and to orange (ZnFe2O4/SiO2) by increasing the Zn2+ ion substituting for Co2+ ions.


Synthesis, magnetic and optical properties of core/shell Co1-xZnxFe2O4/SiO2 nanoparticles.

Girgis E, Wahsh MM, Othman AG, Bandhu L, Rao K - Nanoscale Res Lett (2011)

Photographs of CoFe2O4/SiO2 (a), Co0.5Zn0.5Fe2O4/SiO2 (b), and ZnFe2O4/SiO2 (c) nanoparticles fired at 400°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211881&req=5

Figure 7: Photographs of CoFe2O4/SiO2 (a), Co0.5Zn0.5Fe2O4/SiO2 (b), and ZnFe2O4/SiO2 (c) nanoparticles fired at 400°C.
Mentions: Figure 7 shows the photographs of CoFe2O4/SiO2 (Figure 7a), Co0.5Zn0.5Fe2O4/SiO2 (Figure 7b), and ZnFe2O4/SiO2 (Figure 7c) core/shell ferrite nanoparticles fired at 400°C for 2 h, with and without an external magnet effect. It can be seen that all the core/shell nanoparticles show manifestations of ferromagnetic behavior as shown in the photographs where the nanoparticles were attracted to the external magnet. Also, it is clear that the nanoparticles colors were changed from black (CoFe2O4/SiO2), to brown (Co0.5Zn0.5Fe2O4/SiO2), and to orange (ZnFe2O4/SiO2) by increasing the Zn2+ ion substituting for Co2+ ions.

Bottom Line: It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases.On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles.These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications.

View Article: PubMed Central - HTML - PubMed

Affiliation: Solid State Physics Department, National Research Centre, 12311 Dokki, Giza, Egypt. egirgis@gmail.com.

ABSTRACT
The optical properties of multi-functionalized cobalt ferrite (CoFe2O4), cobalt zinc ferrite (Co0.5Zn0.5Fe2O4), and zinc ferrite (ZnFe2O4) nanoparticles have been enhanced by coating them with silica shell using a modified Stöber method. The ferrites nanoparticles were prepared by a modified citrate gel technique. These core/shell ferrites nanoparticles have been fired at temperatures: 400°C, 600°C and 800°C, respectively, for 2 h. The composition, phase, and morphology of the prepared core/shell ferrites nanoparticles were determined by X-ray diffraction and transmission electron microscopy, respectively. The diffuse reflectance and magnetic properties of the core/shell ferrites nanoparticles at room temperature were investigated using UV/VIS double-beam spectrophotometer and vibrating sample magnetometer, respectively. It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases. The cobalt ferrite nanoparticles fired at temperature 800°C; show the highest saturation magnetization while the zinc ferrite nanoparticles coated with silica shell shows the highest diffuse reflectance. On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles. These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications.

No MeSH data available.