Soft Magnetic Properties of Fe-Ni-Nb Alloy Films

Abstract

Relation between soft magnetic properties and local anisotropy fluctuation in Fe-Ni-Nb alloy films measured by the dynamic differential susceptibility method was clarified and discussed in comparison with Fe-Si-Al alloy films. In Fe-Ni-Nb alloy films, excellent soft magnetic properties, μ_eff=6500 at 5 MHz of 1000Å film thickness, were realized. In Fe-Si-Al alloy films, the magnitude of μ_eff is proportional to 1/√S (S: structure constant) and independent of the value of H_K, while in 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 μ_eff is not dependent on the value of S. Rather, this magnitude is dependent on the value of H_k, and is almost equal to 4πM_s/H_k (obtained from a rotational magnetization model in a uniaxal single domain particle).