Enhancement in the magneto-impedance (MI) effect of multi-ribbon

This article describes the use of a magnetic ribbon to create a highly sensitive magnetic sensor. The sensor employs the impedance change in a magnetic ribbon when a radio frequency (RF) current is passed through it and an external magnetic field is applied. To achieve a highly sensitive magnetic sensor, we had to increase the impedance change. We examined stacked magnetic ribbons, each isolated with thin plastic sheets, and interpreted the results by calculating the impedances and relative current in each ribbon. The impedance change was enhanced by stacking the ribbons. However, the effective permeability, which greatly affects the sensitivity, decreased as the number of ribbons increased. Consequently, the double-layered structure provided the maximum sensitivity, which was about three times higher than that of a single-layered structure.