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Home > Issues > Volume 10 (2005) > No.3(pp.77-132)

New Classes of LC Resonators for Magnetic Sensor Device Using a Glass-Coated Amorphous Co83.2B3.3Si5.9Mn7.6 CoMicrowire

Journal of Magnetics, Volume 10, Number 3, 30 Sep 2005, Pages 122-127
Yong-Seok Kim(Department of Physics ,Chungbuk National University), Seong-Cho Yu(Department of Physics ,Chungbuk National University), Myung-Joo Hwang(Department of Physics Education, Kongju National University), Hee-Bok Lee* (Department of Physics Education, Kongju National University)
Abstract
New classes of LC resonators for micro magnetic sensor device were proposed and fabricated. The first type LC resonator (Type I) consists of a small piece of microwire and two cylindrical electrodes at the end of the microwire without direct contact to its ferromagnetic core. In type I resonator the ferromagnetic core of the microwire and cylindrical electrodes act as an inductor and two capacitors respectively to form a LC circuit. The second type LC resonator (Type II) consists of a solenoidal micro-inductor with a bundle of soft magnetic microwires as a core. The solenoidal micro-inductors fabricated by MEMS technique were 500~1000µm in length with 10~20 turns. A capacitor is connected in parallel to the micro-inductor to form a LC circuit. A tiny glass coated Co83.2B3.3Si5.9Mn7.6 microwire was fabricated by a glass-coated melt spinning technique. A supergiant magneto-impedance effect was found in a type I resonator as much as 400,000% by precise tuning frequency at around 518.51 MHz. In type II resonator the changes of inductance as a function of external magnetic field in micro-inductors with properly annealed microwire cores were varied as much as 370%. The phase angle between current and voltage was also strongly dependent on the magnetic field. The drastic increments of magnetoimpedance at near the resonance frequency were observed in both types of LC resonators. Accordingly, the sudden change of the phase angle, as large as 180℃, evidenced the occurrence of the resonance at a given external magnetic field.
Keywords: LC resonator; Magnetic sensor; Glass-coated microwire; Magnetoimpedance; Incremental permeability
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