FeCo基磁芯螺线管巨磁阻抗效应与磁芯长度关系的研究

研究了Fe₃₆Co₃₆Nb₄Si_4.8B_19.2合金薄带为磁芯的螺线管(FeCo基磁芯螺线管)的巨磁阻抗效应与磁芯长度之间的关系.研究结果表明,磁芯长度是影响FeCo基磁芯螺线管巨磁阻抗效应的重要因素.当磁芯长度小于螺线管长度时,磁芯螺线管巨磁阻抗的最大值(ΔZ/Z)_max与磁芯长度呈线性关系,其线性相关系数可以根据电磁学理论推导得到;当磁芯的长度大于螺线管的长度时,由于漏磁作用,(ΔZ/Z)_max与磁芯长度的关系偏离了线性关系,(ΔZ/Z)_max与磁芯长度的关系曲线中有一个极值点,(ΔZ/Z)_max在极值点达到最大.磁芯螺线管巨磁阻抗效应曲线的尖刺部分高度(ΔZ/Z)_T与磁芯长度的关系也有类似的极值点,(ΔZ/Z)_T在极值点达到最大值.磁芯螺线管巨磁阻抗效应曲线的尖刺部分对弱磁场敏感,受磁芯退磁场的影响明显,磁芯的退磁场与磁芯长度呈负指数关系. 关键词： 磁芯螺线管 FeCo基合金薄带 巨磁阻抗效应 磁芯长度

Investigation on the relation between the length of magnetic core and the giant magnetoimpedance effect of solenoid with FeCo-based magnetic core

The relation between the length of the magnetic core (l) and the giant magnetoimpedance(GMI) effect of solenoid with magnetic core of Fe₃₆ Co₃₆ Nb₄Si_4.8 B_19.2 ribbon which annealed with current 32 A/mm² for 10 min, has been investigated. The result shows that there is a sensitive relation between l and GMI. There is a linear relation between the l and the maximum of the GMI (ΔZ/Z)_max when l is smaller than the length of the solenoid l₀. The linear correlation coefficient can be deduced from the electromagnetism theory. It should deviate from the linear relation when l is greater than l₀. There is a maximum value of the (ΔZ/Z)_max when the l reaches the best value. There is a similar relation between the height of the tip like part of the GMI profile (ΔZ/Z)_T and l. There is a maximum value of the (ΔZ/Z)_T when the l is the best value. The tip like part of the GMI profile, which responds to the weak magnetic field sensitively, is influenced by the demagnetizing field. There is a negative exponential relation between the demagnetizing field and the length of the magnetic core l.