Transverse, longitudinal and perpendicular giant magnetoimpedance effects in a compact multiturn meander NiFe/Cu/NiFe trilayer film sensor

A compact multiturn meander NiFe/Cu/NiFe trilayer film giant magnetoimpedance (GMI) sensor, with the width of 100 µm for NiFe film and 60 µm for Cu film, the space of 40 µm and a turn number of 10 is fabricated by the MEMS technique on a silicon substrate. The transverse, longitudinal and perpendicular GMI effects are respectively investigated in the magnetic field range of 0–120 Oe and the frequency range of 1–40 MHz. With the magnetic field it could be up to 86.6% for the transverse GMI effect at 15 MHz and 120 Oe, 166% for the longitudinal GMI effect at 15 MHz and 20 Oe and 165% for the perpendicular GMI effect at 10 MHz and 50 Oe. In addition, there are platform stages, which correspond to the magnetic field range of 0–20 Oe for the transverse GMI effect and 0–10 Oe for the perpendicular GMI effect. Furthermore, the peak of GMI effects covers a large frequency range, which could be up to about several tens of MHz. The GMI platform and the strong GMI effect could be attributed to the demagnetization effect and enhanced electromagnetic coupling from the compact meander sensor structure, respectively. The broad frequency peak originates from the different magnetization process in the straight segment in the meander structure.