Effect of annealing treatments on the microwave electromagnetic properties of amorphous FeCuNbSiB microwires

The amorphous FeCuNbSiB microwires are fabricated by using themelt extraction method and annealed separately at temperaturesT = 573, 673, 723 and 773K for 1h. The effect of annealingtreatment on the microwave electromagnetic properties ofFeCuNbSiB wires/wax composites has been investigated for thefirst time. It is found that in a frequency range of0.5--4.0GHz, the complex permittivity, permeability, magneticand electric loss tangents of FeCuNbSiB wires/wax composites arestrongly dependent on the annealing temperature and frequency.For T = 573, 723 and 773K, two resonance peaks are found atfrequency f = 1.2 and 3.3GHz. However, for T = 673K,only one resonance peak occurs at f = 3.3GHz. The resonancepeak at f = 1.2GHz is believed to be due to thestress-induced anisotropy, while the resonance peak at f =3.3GHz is attributed to the random anisotropy.