Co-Fe-B-Si-Nb非晶丝巨磁阻抗效应的研究

Giant Magneto-Impedance in Co-Fe-B-Si-Nb Amorphous Wires

摘要: 本文利用具有强非晶形成能力的Co₆₃Fe₄B_22.4Si_5.6Nb₅块体非晶合金材料，用熔体抽拉法制备了直径90 μm的Co基非晶丝，对该非晶丝进行了不同温度的退火处理，并且测试了丝材在不同驱动频率下的GMI效应。结果表明，淬态的Co₆₃Fe₄B_22.4Si_5.6Nb₅非晶丝具有非常优异的GMI效应，在驱动频率为1.2 MHz时，阻抗变化率 达到最大，其值接近250%。随着驱动频率的提高，巨磁阻抗曲线逐渐出现了双峰，并且峰值所对应的开关磁场随着频率的升高而增大。淬态Co基非晶丝经退火处理后，由于应力释放造成了环向磁结构的减弱，导致了巨磁阻抗效应的下降。

Abstract: Co-based amorphous alloy wires with diameter of 90μm were prepared using melt extraction method, with bulk amorphous alloys Co₆₃Fe₄B_22.4Si_5.6Nb₅having a strong glass-forming ability. The giant magneto impedance(GMI) effect of the as cast and annealed wires was analyzed at different driving frequencies. The results show that the Co₆₃Fe₄B_22.4Si_5.6Nb₅ cast amorphous wire has an excellent GMI effect. The largest impedance ratio ( ) is as high as 250% at driving frequency of 1.2MHz. As the driving frequency in-creases to exceed 1.2MHz, the double peaks of giant magneto-impedance curve began to appear, and the peaks corresponding to the switching field increase with increase in the frequency. The circular magnetic structure after annealing treatment is weakened due to the release of stress, which leads to the depression of the GMI effect of Co-based amorphous wire.