A micro-machined LC-resonator for high-frequency magnetic sensor applications

The main aim of this study is finding a micro-sized magnetic sensor device with great sensitivity operating at high frequency region. In this report, we introduce a new class of LC-resonator consisting of a micro-inductor fabricated by means of MEMS technique with a bundle of soft magnetic microwire cores and a capacitor connected in parallel to the micro inductor to form a LC circuit. The solenoidal micro-inductors fabricated by MEMS technique were varied from 500~1,000 frac14m in length with 10~20 turns. The core magnetic material is a tiny glass coated amorphous Co_83.2B_3.3Si_5.9Mn_7.6 microwires fabricated by the Taylor-Ulitosky method. The core materials were annealed at various temperatures 150degC, 200CdegC, 250degC, and 300degC for 1 hour in a vacuum to improve soft magnetic properties. The magneto-impedance ratio (MIR) for a micro-LC resonator can be measured at various frequencies to find sharp peaks for maximum sensitivity.