X-ray Diffraction Studies the Superlattices Structure and Coalescence of
Self-assembled FePt Nanoparticles
Tzu-Wen Huang (黃子文), Te-Horn Tu (杜德洪), and Chih-Hao Lee (李志浩)
Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan
30043
The superlattices structure and coalescence of self-assembled FePt nanoparticles was studied
by X-ray diffraction in this work. This material is very promising as future ultrahigh density
recording media after Sun. et al. [1] successfully prepared the self-assembly superlattices films of
FePt nanoparticles. The synthesis of those nanoparticles has been investigated and reported by
thermal deposition and the self-assembled layer always been imaged by TEM [2-4]. Although
narrow particle sizes distribution provides well order packing and hexagonal array in a small local
spot of the sample, the coalescence and structure of whole packing layers couldn’t be studied by
TEM. X-ray scattering technique whish provide the statistical average over a large area is very
important in practical appreciation.
FePt nanoparticles whish sizes of about 3 nm follow the method developed by Sun. were
prepared by the simultaneous reduction of platinum acetylacetonate and thermal decomposition of
iron pentacarbonyl. As that FePt nanoparticles deposition on Si (001) was found the
three-dimension FCC like superlattices structure. Figure (a) and (b) show that closest packing plane
(111) and diffraction (220) had been found with the (111) d-spacing equals to 6.51 nm. The
deduced from the coherent length of the diffraction peak by Scherrer formula well packing
thickness is about 35-45 layers.
10
1E-3
1E-4
1E-5
1E-6
(a)
1E-8
0
1
2
qz (1/nm)
3
4
220
0.1
0.01
1 -1 1
Intensity (arb. units)
Intensity (arb. units)
Intensity (arb. units)
0.1
0.01
1E-7
(b)
Reflectivity FePt on Si(111)
1
1
0.1
-5
1 -1 1 projection
5
10
15
20
25
30
35
q (1/nm)
FePt/Si
FePt/Kapton
1E-3
0.0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
q (1/nm)
Fig. (a) The superlattices peak (111) and (b) in plane superlattices peak (220) of
self-assembly FePt nanoparticles.
Reference
[1] S. Sun, C.B. Murray, D. Weller, L. Folks, A. Moser, Science 287 (2000) 1989.
[2] Zeng H.; Sun S.; Vedantam T.S.; Liu J.P.; Dai Z. –R. and Wang Z. –L., Appl. Phys. Lett., Vol. 80,
No. 14, (2002) 2583.
[3] T. J. Klemmer, N. Shukla, C. Liu, X. W. Wu, E. B. Svedberg, O. Mryasov, R. W. Chantrell, and
D. Weller, Appl. Phys. Lett., Vol. 81, No. 12, (2003) 2220.
[4] J. W. Harrell, S. Wang, D. E. Nikles and M. Chen, Appl. Phys. Lett., Vol. 79, No. 26, (2001)
4393.