Supplementary information
Exchange coupling driven omnidirectional rotatable
anisotropy in ferrite doped CoFe thin film
Guozhi Chai1, Nguyen N. Phuoc1, and C. K. Ong2*
Temasek Laboratories, National University of Singapore, Singapore 117411, Singapore,
Centre for Superconducting and Magnetic Materials, Department of Physics, National
University of Singapore, Singapore 117542, Singapore,
*
email: phyongck@nus.edu.sg
1
X-Ray Diffraction (XRD) study of the ferrite doped CoFe thin films
The XRD results of the undoped and 11 at % ferrite doped CoFe thin films are shown in
figure S1. As the only main peak is around 45 degree which is belong to (110) peak of
bcc structure CoFe alloys. No other peak belong to Ferrite were observed. Our ferrite
doped CoFe thin films are basically granular thin films consist of CoFe nanocrystalline
and amorphous phase.
We also perform XRD study to compare the peaks around 43-47 degree for ferrite
doped CoFe thin films with different concentration and results were shown in figure S2.
The peak shifts to smaller angle while the doping concentration of ferrite increased. The
details of the peak values are shown in table S1. This implies the lattice constant of the
films is increased with the higher composition of ferrite. The full width at half maximum
(FWHM) is obtained by fitting the XRD spectrum. The fitting results of the FWHM of
ferrite doped CoFe thin films are shown in Table S1. The grain sizes can be calculated
from the FWHM and diffraction angle of the samples with Scherrer equation1
D
K
B cos 
where, D is the grain size, K is the constant with value 0.89, λ is the wave length of X
Ray, B is the full width at half maximum (FWHM), θ is the diffraction angle. The grain
sizes first increase from about 16.5 nm to 17.5 nm then decrease to about 15 nm while the
doping concentration increase from 0 to 16 at %.
References:
1
Patterson A L 1939 Phys. Rev. 56 978.
2
Figure S1. XRD of undoped and 11 at % concentration ferrite doped CoFe thin films, the
main peak of CoFe ((110) peak of bcc structure) is observed in doped and undoped
samples.
Figure S2. The XRD spectrum shows perks shift to the right as the doping concentration
increases indicating grain sizes shrink as doping increases. The numbers at the left corner
mean the concentration of the doped elements.
3
Table S1. The FWHM of XRD and calculated grain sizes of ferrite doped CoFe thin films
Doping concentration
Diffraction angle
FWHM
Calculated grain sizes
(at %)
(°)
(°)
(nm)
0
44.89
0.66
16.7
7
44.73
0.68
16.3
9
44.77
0.63
17.6
11
44.77
0.66
16.8
16
44.67
0.73
15.1
4