电流退火及长度对玻璃包裹丝GMI效应的影响

摘要

Amorphous Fe73.5Cu1.0Nb3.0Si13.5B9 microwires are prepared by the Taylor-Ulitovsky method.Then,the as-prepared microwires are annealed by cuurent annealing.The best performance microwires are obtained at annealing current density of 4.2 × 107 A/m2 because of the suitable volume ratio between nanocrystalline and amorphous phases.Influence of length on giant magnetoimpedance effect and magnetic properties for microwires is then investigated.The results show that anisotropy field increases and the GMI ratio descreases with decreased length of the wire.Demagnetizing field model gives a reasonable explanation.%采用高频感应加热熔融快淬法制备了Fe73.5Cu1.0Nb3.0Si13.5B9非晶玻璃包裹丝.首先对制备态包裹丝进行电流退火,结果发现电流密度为4.2×107 A/m2时,退火得到的玻璃包裹丝性能最佳,原因是此时有合适的纳米晶体积比例.进而研究了长度对其磁性和巨磁阻抗效应的影响.结果表明,随着长度的减小,微丝的各项异性场增大,磁阻抗比减小.采用退磁场模型给予了合理解释.