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Strong textured SmCo5 nanoflakes with ultrahigh coercivity prepared by multistep (three steps) surfactant-assisted ball milling.

Zuo WL, Zhao X, Xiong JF, Zhang M, Zhao TY, Hu FX, Sun JR, Shen BG - Sci Rep (2015)

Bottom Line: The high coercivity of 26.2 kOe for SmCo5 nanoflakes are obtained by multistep (three steps) surfactant-assisted ball milling.The magnetic properties, phase structure and morphology are studied by VSM, XRD and SEM, respectively.The results demonstrate that the three step ball-milling can keep more complete crystallinity (relatively less defects) during the process of milling compared with one step high energy ball-milling, which enhances the texture degree and coercivity.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.

ABSTRACT
The high coercivity of 26.2 kOe for SmCo5 nanoflakes are obtained by multistep (three steps) surfactant-assisted ball milling. The magnetic properties, phase structure and morphology are studied by VSM, XRD and SEM, respectively. The results demonstrate that the three step ball-milling can keep more complete crystallinity (relatively less defects) during the process of milling compared with one step high energy ball-milling, which enhances the texture degree and coercivity. In addition, the mechanism of coercivity are also studied by the temperature dependence of demagnetization curves for aligned SmCo5 nanoflakes/resin composite, the result indicates that the magnetization reversal could be controlled by co-existed mechanisms of pinning and nucleation.

No MeSH data available.


Related in: MedlinePlus

The XRD patterns of (a) starting SmCo5 compound powder, (b) as-milled SmCo5 powder with BM time from 4 to 24 h, (c) aligned sample of SmCo5 nanoflakes with BM time of 24 h.
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f2: The XRD patterns of (a) starting SmCo5 compound powder, (b) as-milled SmCo5 powder with BM time from 4 to 24 h, (c) aligned sample of SmCo5 nanoflakes with BM time of 24 h.

Mentions: Figure 2(a) shows the XRD pattern of starting SmCo5 compound powder, which crystallizes primarily in the hexagonal SmCo5 phase (JCPDS PD#65–4844) and with minor impurity. The XRD patterns of as-milled samples are shown in Fig. 2(b). It can be seen that the diffraction peaks become broader with increasing the BM time, which is due to the grain refinement and the introduction of the internal stress during the BM process. The average crystallite size calculated via Scherrer’s formula is approximately 20 nm, 12 nm, and 6 nm, and the internal strain is about 0.16%, 0.32%, and 0.31%, corresponding to the ball milling time of 4 h, 12 h, and 24 h, respectively. Because of the relatively low BM energy, especially for 4 h milling, the broadening diffraction peaks mainly come from grain refinement. Therefore, this broadening also demonstrates that the low BM energy (150 rpm) is effective in the grain refinement. Because of the low energy instead of high energy in the initial stage of BM, the defects of crystalline structure can be decreased in the whole BM process. In addition, the XRD pattern of aligned sample (milled for 24 h) is shown in Fig. 2(c). It can be seen that the diffraction intensity of (00l) crystalline planes dramatically enhances whereas that of the other peaks almost disappear, suggesting that a strong (00l) alignment is obtained for the aligned sample (the easy magnetization directions along the c-axis).


Strong textured SmCo5 nanoflakes with ultrahigh coercivity prepared by multistep (three steps) surfactant-assisted ball milling.

Zuo WL, Zhao X, Xiong JF, Zhang M, Zhao TY, Hu FX, Sun JR, Shen BG - Sci Rep (2015)

The XRD patterns of (a) starting SmCo5 compound powder, (b) as-milled SmCo5 powder with BM time from 4 to 24 h, (c) aligned sample of SmCo5 nanoflakes with BM time of 24 h.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4536656&req=5

f2: The XRD patterns of (a) starting SmCo5 compound powder, (b) as-milled SmCo5 powder with BM time from 4 to 24 h, (c) aligned sample of SmCo5 nanoflakes with BM time of 24 h.
Mentions: Figure 2(a) shows the XRD pattern of starting SmCo5 compound powder, which crystallizes primarily in the hexagonal SmCo5 phase (JCPDS PD#65–4844) and with minor impurity. The XRD patterns of as-milled samples are shown in Fig. 2(b). It can be seen that the diffraction peaks become broader with increasing the BM time, which is due to the grain refinement and the introduction of the internal stress during the BM process. The average crystallite size calculated via Scherrer’s formula is approximately 20 nm, 12 nm, and 6 nm, and the internal strain is about 0.16%, 0.32%, and 0.31%, corresponding to the ball milling time of 4 h, 12 h, and 24 h, respectively. Because of the relatively low BM energy, especially for 4 h milling, the broadening diffraction peaks mainly come from grain refinement. Therefore, this broadening also demonstrates that the low BM energy (150 rpm) is effective in the grain refinement. Because of the low energy instead of high energy in the initial stage of BM, the defects of crystalline structure can be decreased in the whole BM process. In addition, the XRD pattern of aligned sample (milled for 24 h) is shown in Fig. 2(c). It can be seen that the diffraction intensity of (00l) crystalline planes dramatically enhances whereas that of the other peaks almost disappear, suggesting that a strong (00l) alignment is obtained for the aligned sample (the easy magnetization directions along the c-axis).

Bottom Line: The high coercivity of 26.2 kOe for SmCo5 nanoflakes are obtained by multistep (three steps) surfactant-assisted ball milling.The magnetic properties, phase structure and morphology are studied by VSM, XRD and SEM, respectively.The results demonstrate that the three step ball-milling can keep more complete crystallinity (relatively less defects) during the process of milling compared with one step high energy ball-milling, which enhances the texture degree and coercivity.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.

ABSTRACT
The high coercivity of 26.2 kOe for SmCo5 nanoflakes are obtained by multistep (three steps) surfactant-assisted ball milling. The magnetic properties, phase structure and morphology are studied by VSM, XRD and SEM, respectively. The results demonstrate that the three step ball-milling can keep more complete crystallinity (relatively less defects) during the process of milling compared with one step high energy ball-milling, which enhances the texture degree and coercivity. In addition, the mechanism of coercivity are also studied by the temperature dependence of demagnetization curves for aligned SmCo5 nanoflakes/resin composite, the result indicates that the magnetization reversal could be controlled by co-existed mechanisms of pinning and nucleation.

No MeSH data available.


Related in: MedlinePlus