Static and Dynamic Properties of Fe-Si-B-Nb-Cu Nanocrystallized Ferromagnetic Glass-Coated Microwires From 20 C to 350 C

In this paper, nanocrystallized glass coated microwires have been elaborated. Their magnetic properties have been determined and compared to amorphous Co-based microwires. We studied two alloys in the Finemet family and two geometries of microwires. We observed a dependence of the magnetic anisotropy with both the composition and the diameters of the microwires. We also performed permeability measurement in the 200 MHz to 4 GHz range up to 350degC. We report a fair stability of the microwave properties, and also their reversible behavior. These properties are very attractive for high frequency high temperature applications. This contrasts with Co-based microwires that exhibit poor thermal stability. The origin of the anisotropy in nanocrystallized microwires is discussed