Soft Magnetic Properties of Fe-Ni-Nb Alloy Films
The relation between the soft magnetic properties and local anisotropy fluctuation measured by the dynamic differential susceptibility method in Fe-Ni-Nb alloy films was clarified and discussed in comparison with Fe-Si-Al alloy films. Fe-Ni-Nb alloy films with excellent soft magnetic properties, 5 MHz values of ¿eff = 6500 for 1000 Å thick films were obtained. For Fe-Si-Al alloy films, the magnitude of ¿eff = 6500 is proportional to 1/S2 (where S is a structure constant) and independent of the value of Hk, while for Fe-Ni-Nb alloy films, the value of S is about one-tenth of that in Fe-Si-Al alloy films, and the magnitude of ¿eff 6500 does not depend on S. Rather, this magnitude is dependent on the value of Hk, and is almost equal to 4¿Ms/Hk, obtained from a rotational magnetization model in a uniaxial single-domain particle.
Local anisotropy fluctuation on the permeability of sputtered sendust alloy films.
Precise concentration dependence of μeff in films was clarified in a concentration area around bulk Sendust alloy. The dynamic differential susceptibility measurement proposed by H. Hoffmann was applied to the same films to evaluate the magnetic inhomogeneities normally represented as magnetic skew and ripple. Influence of the local magnetic anisotropy on μeff of the films is discussed in detail. To realize excellent soft magnetic properties, especially at high frequency, a high degree of preferred orientation of grains or of random orientation of grains is suggested.
Magnetic Properties and Annealing Behavior of Electrodeposited NiFeS Thin Films
Zero magnetostrictive films of FeNi with sulfur contents up to ∼6.5% by weight were prepared by electrodeposition from electrolytes containing thiourea. The total sulfur content in the films increased linearly with thiourea coacentration. The Hc varied from about 10 Oe for no thiourea, down through a broad minimum of about 4 Oe at intermediate thiourea concentrations. The dispersion α90 also went through a broad minimum in this range; values as low as 1° were obtained. Hk was constant at 2.95±0.1 Oe above ∼1% sulfur. The effects of thiourea on Hc, Hk, and α90 are interpreted in terms of its influence on crystallite size and shape, on the smoothness of the film, on the impurity content, and on the planar stresses in the film. With this electrolyte, film compositions were constant throughout their thickness to ±0.2% Ni. Exposure of these films to 60°C in a saturating field parallel to their easy axis produced no changes in Hc, Hk, or α90 for times up to 2000 min. In a transverse field, the change in propert...