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|Title: ||Magnetic and electrical properties of amorphous CoFeB films|
|Authors: ||S. U. Jena|
Y. T. Chen
Y. D. Yao
J. M. Wu
C. C. Lee
T. L. Tsai
Y. C. Chang
|Issue Date: ||2018-07-04T08:22:22Z
|Publisher: ||J. Appl. Phys|
|Abstract: ||Abstract: CoFeB films were deposited on glass substrate by the sputtering method. From x-ray-diffraction and
electron-diffraction-ring patterns, the major phase in the as-deposited CoFeB film is amorphous or
nanocrystalline. However, we could also identify a minor CoFe110 crystalline phase in the film.
We have tried to suppress this crystalline phase by changing the Ar partial pressure PAr during
deposition and found that the optimal condition is PAr= 510−3 Torr. Because the electrical
resistivity value of the film is in general larger than 100 cm, it also indicates that the
amorphous phase is dominant. From the temperature coefficient of resistance measurement, we
learn that the amorphous phase in the CoFeB film crystallizes in succession at two higher
temperatures Tcr1 and Tcr2 than the room temperature RT. Besides the electrical properties, the
film thickness tf dependence of saturation magnetization Ms, saturation magnetostriction s,
and coercivity Hc has also been discussed. From the Auger-depth profile analysis, it is found that
there is one CoOx with 0.4x1 oxide layer, about 15 Å in thickness, lying on the top surface
of the CoFeB film, and another CoOx oxide layer, about 20 Å, lying near the CoFeB/glass interface.
At RT CoOx is supposed to be paramagnetic. However, due to the proximity effect between CoOx
and CoFeB, the CoOx layers may become ferromagnetic with the average magnetization Mox. By
fitting the Ms data as a function of 1/tf, we can show that the last conjecture is correct, and Mox
is not zero. The CoOx layer plays an important role on Ms,s, and Hc of the CoFeB films with tf
ranging from 50 to 503 Å. © 2006 American Institute of Physics.
|Appears in Collections:||[光電科學研究所] 期刊論文|
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