• 한국자기학회지
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• 제27권4호
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• pp.135-139
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• 2017

직경 $190{\mu}m$ Cu 와이어에 $Ni_{80}Fe_{20}$ 연자성 물질을 전기도금법으로 증착하여 금속 코어/연자성 쉘 구조의 복합 와이어를 제작하고 이 와이어에서 자기임피던스 효과(MI 효과)를 연구하였다. 원통 좌표계에서 복합 와이어의 임피던스 텐서의 두 대각 성분 $Z_{{\theta}{\theta}}$와 $Z_{zz}$는 z 방향으로 가한 자기장에 대해 큰 MI 효과를 나타낸 반면, 비대각 임피던스 $Z_{{\theta}z}$의 MI 효과는 매우 약하게 나타났다. 비대각 자기임피던스 효과가 큰 복합 와이어를 만들기 위해 비틀림 스트레인 하에서 전기도금하는 방법을 시도하였다. Cu 와이어의 한쪽 끝을 약 $270^{\circ}$ 이상 회전한 상태에서 전기도금 된 복합 와이어는 뚜렷하게 증대된 비대각 MI 효과를 보였으며 $360^{\circ}$ 회전한 상태에서 도금 된 와이어에서 최대의 비대각 MI 효과를 얻을 수 있었다. 본 연구를 통해 비대각 MI 효과가 큰 복합와이어를 제작하는 방법을 개발한 것은 금속 코어/자성 쉘 복합 와이어의 자기센서 소재로써의 응용가능성을 높일 것으로 기대된다.

• Journal of Magnetics
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• 제13권2호
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• pp.65-69
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• 2008

The magneto impedance (MI) behaviors of patterned $Co_{30}Fe_{34}Ni_{36}$ microwire were investigated with respect to its shape variation. After preparing $Co_{30}Fe_{34}Ni_{36}$ microwires using electrodeposition and photolithography methods, impedance measurements were conducted to compare the MI ratios of the devices with different aspect ratios. As a result, the anisotropy field and transverse permeability were found to be strongly affected by the aspect ratio of the device. The external field value at the maximum impedance and maximum sensitivity of the device was found to increase with increasing device width, which was attributed to the increased transverse anisotropy with decreasing aspect ratio. While an increase in the thickness also contributed to an increase in the MI ratio, a variation in the thickness not only increased the anisotropic field, but the variation in the MI ratio was as also affected by the skin effect. Conversely, the MI ratios of the present devices were hardly affected by variations in the length. Considering the typical aspect ratios of our devices, it was expected that the length effect would emerge when the aspect ratio was reduced to less than 10. Nevertheless, our results show that for the practical application of MI devices, the MI characteristics can be optimized by tailoring the aspect ratio of the devices.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1997년도 한국재료학회 춘계학술발표회
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• pp.38-38
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• 1997

In the paper, we investigate the magneto-impedance(MI) effect of the Fe-Co-B Amorphous magnetic film, the amorphous magnetic film having near zero magnetostostriction is fabricated by using the sputtering methode, and then annealed in magnetic field. When the external magnetic field is directly applied to the fabricated film, the voltage amplitude between both side of the magnetic film varies about 22% at 10[MHz] and the impedance varies about 21% at 10[Oe]. Thus, we find that the fabricated magnetic film has the characteristics of high-quality sensor element.

• 한국전기전자재료학회논문지
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• 제17권1호
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• pp.52-58
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• 2004

Magneto-Impedance(MI) sensor is a highly sensitive sensor, which was able to detect a weak geomagnetic field. It also has a merit to be able to build in the low power system. In this study, their magnetic permeability and anisotropy field(H$\sub$k/) as a function of some different thickness of sputtered amorphous CoZrNb films with zero-magnetostriction and soft magnetic property are investigated. In order to make a uniaxial anisotropy, film was subjected to the post annealing in a static magnetic field with 1KOe intensity at 250, 300, and 320$^{\circ}C$ respectively for 2 hours. Magnetic properties of films are measured by using a M-H loop tracer. Magnetic permeability of a film is measured over the frequency range from 1 ㎒ to 750㎒. By thickening a CoZrNb film relatively, magnetic permeability and impedance are examine to design the. MI sensor which drives at 50㎒, and thereof fabricated the MI sensor which drives at the 50㎒.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.132-135
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• 2002

MI(Magneto-Impedance) sensor which is made by thin films has significantly high detecting sensitivity in weak magnetic field. It also has a merit to be able to build in the low power system. Its structure is simple, which makes it easier to prepare a miniature. In this study, its magnetic permeability and anisotropy field($H_{k}$) as a function of a thickness of sputtered amorphous CoZrNb films with zero-magnetostriction and soft magnetic property are investigated. In order to make a uniaxial anisotropy, film was subjected to the post annealing in a static magnetic field with 1KOe intensity at 250, 300, and $320^{\circ}C$ respectively for 2 hours. Magnetic properties of film are measured by using a MH loop tracer. Its magnetic permeability of a film is measured over the frequency range 1 MHz to 750MHz. And, it was examined on the permeability and impedance to design the MI sensor which acts at 50MHz by thickening a CoZrNb film relatively, and fabricated the MI sensor which acts at the 50MHz.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.778-781
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• 2002

MI(Magneto-Impedance) sensor which is made by thin films has significantly high detecting sensitivity in weak magnetic field. It also has a merit to be able to build in the low power system. Its structure is simple, which makes it easier to prepare a miniature. In this study, its magnetic permeability and anisotropy field$(H_k)$ as a function of a thickness of sputtered amorphous CoZrNb films with zero-magnetostriction and excellent soft magnetic property are investigated. In order to make a uniaxial anisotropy, film was subjected to the post annealing in a static magnetic field with 1KOe intensity at 250, 300, and $320^{\circ}C}$ respectively for 2 hours. Anisotropy field$(H_k)$ of film is measured by using a MH loop tracer. Its magnetic permeability of a film is measured over the frequency range from 1 MHz to 750MHz. It has shown that the magnetic permeability of amorphous CoZrNb film is decreased due to the skin effect with increasing a thickness of the CoZrNb film, and hence its driving frequency is lowered. And, it was examined on the permeability and impedance to fabricate the MI sensor which acts at a low frequency by thickening a CoZrNb film relatively.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 somma/kms meeting
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• pp.68-68
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• 2003

• 센서학회지
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• 제32권4호
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• pp.232-237
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• 2023

This paper presents a system for estimating the position of a magnet using a magnetic sensor. An algorithm is presented to analyze the waveform and output voltage values of the magnetic field generated at each position when the magnet moves and to estimate the position of the magnet based on the analyzed data. Here, the magnet is sufficiently small to be inserted into a blood vessel and has a micro-magnetic field of hundreds of nanoteslas owing to the small size and shape of the guide wire. In this study, a highly sensitive magneto-impedance (MI) sensor was used to detect these micro-magnetic fields. Nine MI sensors were arranged in a 3×3 configuration to detect a magnetic field that changes according to the position of the magnet through the MI sensor, and the voltage value output was polynomially regressed to specify a position value for each voltage value. The accuracy was confirmed by comparing the actual position value with the estimated position value by expanding it from a 1D straight line to a 3D space. Additionally, we could estimate the position of the magnet within a 3% error.

• 센서학회지
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• 제16권5호
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• pp.389-393
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• 2007

Soft ferromagnetic materials are very useful for many sensors using magnetic materials demanding high permeability, low coercivity and low hysteresis loss. Among them, FeCoSiBNi amorphous magnetic films show a good impedance change (about 5.01 %/Oe, at 10 MHz) by the exterinal magnetic field in this experiment. The magnetic films are produced by melt-spun method, one of the rapid solidification process. Ribbon shape wires were made from the films, and let them annealed in DC magnetic field to increase the maximum Giant Magneto Impedance ratio. Field annealing decreases the stress and changes the effective anisotropy. Thus, we can find that the impedance change (200.47 %) is improved and the fabricated magnetic wire has characteristics of good sensor element.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 IUMRS-ICEM ABSTRACT BOOK
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• pp.126.2-126
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• 1998