摘要
以去掉玻璃包覆层的Co68Fe4.5Si13.5B14非晶微丝为研究对象,观察电流退火对微丝巨磁阻抗效应的影响。当退火电流为30mA,较长的退火时间有利于材料性能的改善,退火时间延长,非晶芯丝的最大磁阻抗比和磁场灵敏度都会增高。当退火时间为90s,磁场强度H=79.6A/m、频率f=3MHz时,阻抗最大变化率增加到142.2%,磁场灵敏度达到1.79%/(A/m),电流退火改善了微丝的巨磁阻抗效应和磁场灵敏度。通过磁力显微镜观察了电流退火前后芯丝的磁畴结构,发现由于退火处理前芯丝中存在间距较窄的平行轴向磁畴,几乎没有周向磁畴,微丝的巨磁阻抗效应很低;电流退火处理后感应微丝产生周向螺旋状磁畴,同时轴向磁畴变小,微丝软磁性能变好,微丝的巨磁阻抗效应提高。
Influence of current annealing on the giant magnetoimpedance（GMI） effect of Co68Fe4.5Si13.5B14 microwires was studied.The result showed that,for annealing current of 30mA,the GMI effect and its magnetic field sensitivity of metal wire increase with extending current annealing time.The maximum GMI ratio of 142.2% and responding magnetic field sensitivity of 1.79%/（A/m） were obtained for sample annealed at 30mA for 90s,when the magnetic field is 79.6A/m and frequency is 3MHz.Magnetic domain structure of microwires before and after current annealing was observed by magnetic force microscopy.It showed that parallel axial magnetic domain with a narrower spacing exists in the metal core,and there is almost not circumferential magnetic domain.So,giant magnetoimpedance effect of microwires is very low.The circumferential magnetic domain with helicoidal structures is induced by current annealing.Meanwhile,axial magnetic domain of the wire gets weakened,and its soft magnetic properties are modified,which resultantly improves its giant magnetoimpedance effect.
出处
《磁性材料及器件》
CSCD
北大核心
2011年第2期13-16,24,共5页
Journal of Magnetic Materials and Devices
关键词
玻璃包覆微丝
电流退火
巨磁阻抗效应
磁畴
glass-coated microwires
current annealing
giant magneto-impedance effect
magnetic domain
