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Morphology and magnetic properties of Fe3O 4 nanodot arrays using template-assisted epitaxial growth.

Guan XF, Chen D, Quan ZY, Jiang FX, Deng CH, Gehring GA, Xu XH - Nanoscale Res Lett (2015)

Bottom Line: The calculated nanodot density was as high as 0.18 Tb in.(-2) when D = 40 nm.Results showed that magnetic properties could be tailored through the morphology of nanodots.Therefore, Fe3O4 nanodot arrays may be applied in high-density magnetic storage and spintronic devices.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education and School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004, China, guanxiaofen325@163.com.

ABSTRACT
Arrays of epitaxial Fe3O4 nanodots were prepared using laser molecular beam epitaxy (LMBE), with the aid of ultrathin porous anodized aluminum templates. An Fe3O4 film was also prepared using LMBE. Atomic force microscopy and scanning electron microscopy images showed that the Fe3O4 nanodots existed over large areas of well-ordered hexagonal arrays with dot diameters (D) of 40, 70, and 140 nm; height of approximately 20 nm; and inter-dot distances (D int) of 67, 110, and 160 nm. The calculated nanodot density was as high as 0.18 Tb in.(-2) when D = 40 nm. X-ray diffraction patterns indicated that the as-grown Fe3O4 nanodots and the film had good textures of (004) orientation. Both the film and the nanodot arrays exhibited magnetic anisotropy; the anisotropy of the nanoarray weakened with decreasing dot size. The Verwey transition temperature of the film and nanodot arrays with D ≥ 70 nm was observed at around 120 K, similar to that of the Fe3O4 bulk; however, no clear transition was observed from the small nanodot array with D = 40 nm. Results showed that magnetic properties could be tailored through the morphology of nanodots. Therefore, Fe3O4 nanodot arrays may be applied in high-density magnetic storage and spintronic devices.

No MeSH data available.


FC-ZFC curves of Fe3O4film and dot arrays withD = 40, 70, and 140 nm.
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Fig6: FC-ZFC curves of Fe3O4film and dot arrays withD = 40, 70, and 140 nm.

Mentions: Plots of field cooling-zero field cooling (FC-ZFC) magnetization versus temperature between 10 and 300 K are shown in Figure 6. A magnetic field of 50 Oe had been applied on the plane during measurement. The Tv obtained was around 120 K for the Fe3O4 film and arrays with D = 140 and 70 nm, close to that of the bulk Fe3O4[23]. However, Tv was undetectable at D = 40 nm. Normally, the presence of Tv is used as an evidence that the sample has a perfect stoichiometry of Fe:O = 3:4. The identity of the sample with D = 40 nm had been confirmed to be Fe3O4 based on the XRD pattern. The undetected Tv may be attributed to its small particle size and relatively large inter-particle spacing. The hopping energy barrier between different Fe sites within the nanodot was relatively small compared with the inter-nanodot tunneling barrier, so no Tv was observed in the sample [24].Figure 6


Morphology and magnetic properties of Fe3O 4 nanodot arrays using template-assisted epitaxial growth.

Guan XF, Chen D, Quan ZY, Jiang FX, Deng CH, Gehring GA, Xu XH - Nanoscale Res Lett (2015)

FC-ZFC curves of Fe3O4film and dot arrays withD = 40, 70, and 140 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493851&req=5

Fig6: FC-ZFC curves of Fe3O4film and dot arrays withD = 40, 70, and 140 nm.
Mentions: Plots of field cooling-zero field cooling (FC-ZFC) magnetization versus temperature between 10 and 300 K are shown in Figure 6. A magnetic field of 50 Oe had been applied on the plane during measurement. The Tv obtained was around 120 K for the Fe3O4 film and arrays with D = 140 and 70 nm, close to that of the bulk Fe3O4[23]. However, Tv was undetectable at D = 40 nm. Normally, the presence of Tv is used as an evidence that the sample has a perfect stoichiometry of Fe:O = 3:4. The identity of the sample with D = 40 nm had been confirmed to be Fe3O4 based on the XRD pattern. The undetected Tv may be attributed to its small particle size and relatively large inter-particle spacing. The hopping energy barrier between different Fe sites within the nanodot was relatively small compared with the inter-nanodot tunneling barrier, so no Tv was observed in the sample [24].Figure 6

Bottom Line: The calculated nanodot density was as high as 0.18 Tb in.(-2) when D = 40 nm.Results showed that magnetic properties could be tailored through the morphology of nanodots.Therefore, Fe3O4 nanodot arrays may be applied in high-density magnetic storage and spintronic devices.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education and School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004, China, guanxiaofen325@163.com.

ABSTRACT
Arrays of epitaxial Fe3O4 nanodots were prepared using laser molecular beam epitaxy (LMBE), with the aid of ultrathin porous anodized aluminum templates. An Fe3O4 film was also prepared using LMBE. Atomic force microscopy and scanning electron microscopy images showed that the Fe3O4 nanodots existed over large areas of well-ordered hexagonal arrays with dot diameters (D) of 40, 70, and 140 nm; height of approximately 20 nm; and inter-dot distances (D int) of 67, 110, and 160 nm. The calculated nanodot density was as high as 0.18 Tb in.(-2) when D = 40 nm. X-ray diffraction patterns indicated that the as-grown Fe3O4 nanodots and the film had good textures of (004) orientation. Both the film and the nanodot arrays exhibited magnetic anisotropy; the anisotropy of the nanoarray weakened with decreasing dot size. The Verwey transition temperature of the film and nanodot arrays with D ≥ 70 nm was observed at around 120 K, similar to that of the Fe3O4 bulk; however, no clear transition was observed from the small nanodot array with D = 40 nm. Results showed that magnetic properties could be tailored through the morphology of nanodots. Therefore, Fe3O4 nanodot arrays may be applied in high-density magnetic storage and spintronic devices.

No MeSH data available.