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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.


Related in: MedlinePlus

SEM images for the PAA templates and Fe3O4dot arrays. (a) Ultrathin PAA template, (b) cross section of the PAA, (c) Fe3O4 nanodot array together with a partially removed PAA template, and Fe3O4 nanodot arrays with various sizes - the average dot sizes and inter-dot periods are (d) approximately 40 and approximately 67 nm, (e) approximately 70 and approximately 115 nm, and (f) approximately 140 and approximately 160 nm, respectively.
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Fig1: SEM images for the PAA templates and Fe3O4dot arrays. (a) Ultrathin PAA template, (b) cross section of the PAA, (c) Fe3O4 nanodot array together with a partially removed PAA template, and Fe3O4 nanodot arrays with various sizes - the average dot sizes and inter-dot periods are (d) approximately 40 and approximately 67 nm, (e) approximately 70 and approximately 115 nm, and (f) approximately 140 and approximately 160 nm, respectively.

Mentions: Ultrathin PAA templates with pore diameters of 38, 67, and 137 nm were fabricated. Figure 1a shows a well-ordered array of circularly shaped holes with a pore diameter of 67 nm. Figure 1b is the cross section of this PAA template, with a thickness of approximately 200 nm. The high-quality ultrathin PAA template is the key in preparing epitaxial Fe3O4 nanodot arrays. When the PAA template was partially removed, the Fe3O4 nanodot arrays and the cover of the PAA template were clearly observed, as shown in Figure 1c. The resulting nanodot arrays have respective dot diameters (D) and inter-dot distances (Dint) of approximately 40 and approximately 67 nm (Figure 1d), approximately 70 and approximately 115 nm (Figure 1e), and approximately 140 and approximately 160 nm (Figure 1f). These D were a slightly larger than the pore diameter of PAA, which may be due to the diffusion of atoms during deposition and annealing. The nanodot density was estimated using the following equation [15]: . As shown in Figure 1d, the dot density can be as high as 0.18 Tb in.−2, using Fe3O4 nanodot arrays with D and Dint down to 40 and 67 nm.Figure 1


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)

SEM images for the PAA templates and Fe3O4dot arrays. (a) Ultrathin PAA template, (b) cross section of the PAA, (c) Fe3O4 nanodot array together with a partially removed PAA template, and Fe3O4 nanodot arrays with various sizes - the average dot sizes and inter-dot periods are (d) approximately 40 and approximately 67 nm, (e) approximately 70 and approximately 115 nm, and (f) approximately 140 and approximately 160 nm, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig1: SEM images for the PAA templates and Fe3O4dot arrays. (a) Ultrathin PAA template, (b) cross section of the PAA, (c) Fe3O4 nanodot array together with a partially removed PAA template, and Fe3O4 nanodot arrays with various sizes - the average dot sizes and inter-dot periods are (d) approximately 40 and approximately 67 nm, (e) approximately 70 and approximately 115 nm, and (f) approximately 140 and approximately 160 nm, respectively.
Mentions: Ultrathin PAA templates with pore diameters of 38, 67, and 137 nm were fabricated. Figure 1a shows a well-ordered array of circularly shaped holes with a pore diameter of 67 nm. Figure 1b is the cross section of this PAA template, with a thickness of approximately 200 nm. The high-quality ultrathin PAA template is the key in preparing epitaxial Fe3O4 nanodot arrays. When the PAA template was partially removed, the Fe3O4 nanodot arrays and the cover of the PAA template were clearly observed, as shown in Figure 1c. The resulting nanodot arrays have respective dot diameters (D) and inter-dot distances (Dint) of approximately 40 and approximately 67 nm (Figure 1d), approximately 70 and approximately 115 nm (Figure 1e), and approximately 140 and approximately 160 nm (Figure 1f). These D were a slightly larger than the pore diameter of PAA, which may be due to the diffusion of atoms during deposition and annealing. The nanodot density was estimated using the following equation [15]: . As shown in Figure 1d, the dot density can be as high as 0.18 Tb in.−2, using Fe3O4 nanodot arrays with D and Dint down to 40 and 67 nm.Figure 1

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.


Related in: MedlinePlus