| The effect of Nb content on the crystallization temperature, hardness and magnetic properties, and the effect of annealing on the magnetic properties of (Co_(0.94-x)Fe_(0.06)Nb_x)_(78)Si₄B_(18) amorphous alloy ribbons was investigated. With increasing Nb content, the crystallization temperature (T_x) and the hardness increased with approximately linear trend but the Curie temperature (T_c) and the saturation magnetization decreased linearly. The coercive force showed a minimum value at x = 6 (at%). The room temperature magnetic moment was decreased at a rate of about 5.6μ_B per Nb atom. In Nb containing alloys of T_x$gt;T_c, the magnetic properties were improved by conventional annealing as well as by magnetic field annealing. The optimum annealing temperature was 450℃. For the alloy of T_c$gt;T_x without Nb, the magnetic properties were improved only by magnetic field annealing. The best magnetic properties, the coercive force of 7 mOe and the maximum permeability of 540,000 were obtained by magnetic field annealing at 350℃ in the alloy containing Nb of x=4 (at %). |
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