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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‚ÄČ=‚ÄČ40 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‚ÄČ‚Č•‚ÄČ70 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‚ÄČ=‚ÄČ40 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.


Hysteresis loops of Fe3O4film and dot arrays withD‚ÄČ=‚ÄČ40, 70, and 140 nm. The H and P means the hysteresis loops of the samples measured at in-plane and out-of-plane to the film directions.
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Fig4: Hysteresis loops of Fe3O4film and dot arrays withD‚ÄČ=‚ÄČ40, 70, and 140 nm. The H and P means the hysteresis loops of the samples measured at in-plane and out-of-plane to the film directions.

Mentions: In-plane (H) and out-of-plane (P) room-temperature hysteresis loops of the Fe3O4 nanodot arrays and the film acquired are shown in Figure 4. The Hc, the squareness factor (S), and the saturation magnetization (Ms) of nanodot arrays and the film are shown in Figure 5. These show that the magnetic in-plane easy-axis anisotropy was observed, and the anisotropy is reduced with the dot size. Possibly, the magnetostrictive anisotropy was greatly reduced by the fast relaxation strain from the dot edges, whereas the shape anisotropy and crystalline anisotropy were released by forming noncontinuous dots [19]. As a result, the smallest nanodots exhibited a weak magnetic anisotropy.Figure 4


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)

Hysteresis loops of Fe3O4film and dot arrays withD‚ÄČ=‚ÄČ40, 70, and 140 nm. The H and P means the hysteresis loops of the samples measured at in-plane and out-of-plane to the film directions.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig4: Hysteresis loops of Fe3O4film and dot arrays withD‚ÄČ=‚ÄČ40, 70, and 140 nm. The H and P means the hysteresis loops of the samples measured at in-plane and out-of-plane to the film directions.
Mentions: In-plane (H) and out-of-plane (P) room-temperature hysteresis loops of the Fe3O4 nanodot arrays and the film acquired are shown in Figure 4. The Hc, the squareness factor (S), and the saturation magnetization (Ms) of nanodot arrays and the film are shown in Figure 5. These show that the magnetic in-plane easy-axis anisotropy was observed, and the anisotropy is reduced with the dot size. Possibly, the magnetostrictive anisotropy was greatly reduced by the fast relaxation strain from the dot edges, whereas the shape anisotropy and crystalline anisotropy were released by forming noncontinuous dots [19]. As a result, the smallest nanodots exhibited a weak magnetic anisotropy.Figure 4

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‚ÄČ=‚ÄČ40 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‚ÄČ‚Č•‚ÄČ70 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‚ÄČ=‚ÄČ40 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.