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Low permeability of NiFe film?

2000

Hi,

We electroplated NiFe thin film (3 to 10 microns).

The composition is around 76/24 or Fe (23-27%) using X'ray analysis. The Hc (coercivity) is very small (smaller than 0.2 Oe) and Ms (Saturation magnetization) is reasonable. But the initial permeability (mu) is too small, around (300 - 600). What is the reasons causing this low permeability?

Thanks alot.

Ouyang, Chien
- Pasadena, California

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Probably your anisotropy field, Hk, is too high. The permeability is inversely proportional to Hk. You may want to try "hard axis annealing" in a strong magnetic field (a few hundred Oe), with the sample hard axis parallel to the field, for a few hours at 150-300 degrees C. For a discussion of this and related issues see P.C. Andricacos and L.T. Romankiw, pp. 220-321, in Advances in Electrochemical Science and Engineering, vol. 3, H. Gerischer and C.W. Tobias (editors), VCH.

Emanuel I. Cooper
IBM - Yorktown Heights, New York
2000