• 한국자기학회지
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• 제5권5호
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• pp.726-729
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• 1995

We investigated the effects of Sm on the microstructure and magnetic properties of Fe-Co Alloy films prepared by a DC triode sputtering. The magnetostriction was found to be changed with the Sm content from positive to negative values, taking a zero magnetostriction was at about 3 at% Sm. The Sm content dependence of magnetostriction was explained by the formation of Sm enriched amorphous phase surrounding the main bcc (Fe,Co) crystalline phase, which was observed by a high resolution transmission electron microscopy.

• 한국자기학회지
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• 제6권3호
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• pp.189-193
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• 1996

Magnetoresistance field sensitivity and magnetostriction were measured as a function of annealing temperature for NiFe/Ag multilayer systems displaying giant magnetoresistance. Key multilayer configurations such as number of NiFe/Ag bilayers and Ag spacer thickness were varied. A high giant magnetoresistance ratio up to 5% with zero magnetostriction and high magnetoresistance field sensitivity was possible to achieve simultaneously with optimal sample geometry and annealing condition.

• 한국전기전자재료학회논문지
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• 제11권5호
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• pp.413-417
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• 1998

In this paper, we investigate frequency dependance of inductance of FeCoB amorphous magnetic films. $(Fe_{1-x}Co_x)_{79}Si_2B_{19}$ was used as the basic composition of amorphous magnetic film having near zero magnetostriction. The amorphous magnetic films were fabricated with x=0.94 and x=0.95 by using sputtering method at high frequency. The films were anneald under non-magnetic field and near crystallization temperatures(30min at $280^{\circ}C$, 30min and 1hr at $400^{\circ}C$, respectively). As the results of the experiments with the fabricated films, the lowest coercive force was 0.084[Oe] at 400[W] of the input power and the crystallization temperature was $360^{\circ}C$ . In the case 30min at 40$0^{\circ}C$ the inductance value in the low frequency with x=0.95 was higher by 488% than that with x=0.94. The quality factor Q was below 0.7 for all samples. We obtained the highest quality value at 400[KHz] with 30min at $280^{\circ}C$ and x=0.94. The value was about 0.62. Also, the quality factor value was about 0.35 at 1[MHz] with 30min at $280^{\circ}C$ and x=0.95.

• 대한기계학회논문집A
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• 제24권12호
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• pp.2909-2916
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• 2000

6.5wt% Si steel is widely known as an excellent magnetic material because its magnetostriction is nearly zero. The AX magnetic properties as magnetostriction of 6.5% Si steel were evaluated and compared with those of conventional 3% Si steel sheet. In this paper, the fracture behavior of the poly crystals and single crystals of Fe-6.5wt%Si alloy has been observed. Single crystals were prepared by Floating Zone(FZ) method, which melts the alloy by the use of high temperature electron beam in pure argon gas condition. And the single crystals were annealed at 500$^{\circ}C$ and 700$^{\circ}C$ respectively and tensile tested at room temperature. According to the result, B2 phase has more good elongation than DO$_3$ phase. It was also found that the fracture surfaces of the single crystals have hairline facets in same direction, and the facets change the direction according to the single crystal phase.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
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• pp.473-479
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• 2000

The nanocrystalline Fe$_{84}$Zr$_{7}$B$_{6}$Cu$_{1}$ $Al_{2}$ alloy was annealed at 450 $^{\circ}C$ and 550 $^{\circ}C$ for l hour to achieve the ultra-soft magnetic properties such as large magnetoimpedence ratio(MIR), the incremental permeability ratio(PR), nearly zero coercivity, zero magnetostriction, etc. The PR and MIR of the sample were measured from 100 kHz to 10 MHz at a cryogenic chamber where the temperature can be varie from 10 K to 300 K. The increment of MIR value is proportional to increasing temperature. The maximum PR values measured at high frequency above 1 MHz remain almost same despite of the temperature variation from 10 K to 300 K except the sharpness in PR curves. However, the maximum PR values measured below 1 MHz show drastic increment at above 150K due to thermal activation of magnetic domains.s.s.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 동계연구발표회 논문개요집
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• pp.202-203
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• 2002

Ribbon type nanocrystalline alloy cores have shown excellent soft magnetic properties in the high frequency range because of small crystalline anisotropy and nearly zero magnetostriction[1]. In present, however ribbon alloys gives some limit in applications such as a large inductor and reactors of PFC circuit, which are required good DC bias property and low loss in the high frequency. Powder alloys with ultra fine grain structure can be an important way to overcome this kind of disadvantage, and to improve the high frequency soft magnetic properties in conventional metallic powder cores[2]. (omitted)

• 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 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.

• 한국재료학회지
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• 제8권3호
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• pp.252-255
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• 1998

본논문은 FeCoCiB계 아몰퍼스 자성박막의 주파수에 따른 자기 임피던스(MI)효과에 관하여 조사한 것이다. 영자왜를 갖는 아몰퍼스 자성박막은 고주파 스파터링법에 의하여 제작하였으며, 자계중 열처리를 행하였다. 제작된 자성박막에 직접 외부자계를 인가했을 때, 자성박막의 양단간의 전압진폭은 120[MHz]에서 약 76.2%의 변화를 보였으며, 임피던스는 2.1%/Oe의 변화가 나타났다. 따라서, 제작한 자성박막은 센서소자로서의 가능성을 갖고 있음을 확인하였다.

• 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.