Abstract
MI sensors are magnetic sensor based on the Magneto Impedance (MI) effect discovered by Mori et al. in 1993. Magnetic sensors with a measurement range of 3 ～ 12 G are mainly used as electromagnetic compasses. The demand for magnetic sensors with wider measurement ranges has increased recently due to the rapid popularization of smart phones and tablets. We investigated the effect of the length of wires on the sensor characteristics to expand the measurement range more than that of the AMI306 electronic compass (measurement range: 12 G). We developed an MI element with a wire length of 0.35 mm that had a 1.5 times wider measurement range than that of the AMI306, while retaining almost the same sensitivity by narrowing the coil pitch and using a demagnetizing field. In addition we clarified the measurement range would be predicted from the anisotropy field of wire in the static magnetization.
