• 한국자기학회지
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• 제18권3호
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• pp.98-102
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• 2008

수직자기이방성을 갖는 $[Pd/Co]_N$와 $[Pd/Co(CoFe)]_N$/FeMn 다층박막 구조를 이용하여 표면자기이방성 효과와 강자성 물질에 따른 보자력(coecivity, $H_c$)과 교환력(exchange bias, $H_{ex}$)의 변화를 관찰하였다. Ta(2.1 nm)/[Pd(3.1/N)/$Co(1.2/N)]_N$/Ta(2.1) 다층박막의 구조에서 반복층수 증가에 따라 보자력 670 Oe까지 선형적으로 증가하였으며, 교환 결합된 구조에서의 보자력은 물질에 따라 같은 증가 경향의 결과를 얻었다. 강자성 물질에 따른 가장 큰 보자력은 Co(600 Oe) > $Co_5Fe_5$(520 Oe) > $Co_8Fe_2$(320 Oe) 크기를 얻었다. 반면 교환력의 경우 반복 층수가 N=3 일 때 각 물질 모두 300 Oe의 결과 값을 얻었으며, 반복층수 3층 이후에는 $300{\sim}200$ Oe 사이에 거의 일정한 크기를 얻었다.

• Journal of Magnetics
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• 제11권1호
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• pp.20-24
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• 2006

Very recently, it was presented that the one dimensional (1D) CuO atomic chains can maintain large magnetic moments. In this work, we analyzed m-resolved density of states (DOS) to understand the peculiar spin polarization occurred in Cu atoms. It was found that the $\mid{m}\mid=1$ states play an essential role in the spin polarization of Cu atoms. In addition, we calculated magnetic anisotropy energy (MAE) and observed that the distribution of MAE is strongly sensitive to the interatomic distance between Cu and O atoms. Besides, it was revealed that the contribution to MAE comes for the second half of Brillouin zone (BZ).

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 동계연구발표회 논문개요집
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• pp.194-195
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• 2002

Fe/Cr/Fe trilayers have attracted much interest from both theoretical and experimental aspects due to many novel magnetic properties such as antiferromagnetic coupling, giant magnetoresistance, oscillatory bilinear and biquadratic coupling [1]. In this work, we report that there is an oscillation of magnetic anisotropy with increasing intervening Cr layer thickness in Fe/Cr/Fe trilayers. (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 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.

• 한국지반공학회논문집
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• 제34권8호
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• pp.5-14
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• 2018

쇄설성 퇴적암의 입자 크기는 암석을 구분하는 기준인 동시에 이방성의 원인이 된다. 이방성은 암석의 강도와 풍화에 영향을 미치는 주 원인 중 하나이다. 경상분지의 영주, 대구, 부산 지역에 분포하는 쇄설성 퇴적암과 화성암을 대상으로 대자율타원체를 결정하고 이방성정도와 모양지수를 통해 이방성을 분석하였다. 외력의 영향이 거의 없는 호성환경에서 퇴적된 사암의 이방성정도는 1.03 이하였다. 단층의 영향을 받은 암석은 1.06, 단층암은 1.14 이상의 이방성 정도를 보였다. 암석의 자기적 이방성은 단층으로부터 거리가 멀어질수록 이방성 정도가 감소하였다. 세립질의 입자로 구성된 이암과 셰일은 일차퇴적구조인 층리가 박층으로 발달하며 이로 인해 단층암과 유사한 크기의 이방성을 보였고 대자율타원체의 모양지수도 편원형을 보였다. 실험 결과로부터 쇄설성퇴적암 중 신선한 이암과 셰일은 단층암과 유사한 이방성을 가지므로 이들 암반과 관련된 구조물의 설계, 시공, 유지관리에서 주의가 필요하다.

• Journal of Magnetics
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• 제6권4호
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• pp.142-144
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• 2001

A method to deduce the rotational magnetization curve from experimental magnetization of partially aligned uniaxial anisotropy system has been investigated. The curve obtained by this process has been evaluated quire close to the theoretical magnetization curve compared to that obtained by linear extrapolation from high field data. This new approach offers better accuracy for the determination of magnetic anisotropy by fitting a calculated magnetization curve to the obversed one.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.463-465
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• 2002

In order to increase perpendicular magnetic anisotropy of magnetic layer and prepare magnetic recording layer with a good quality by epitaxial growth between magnetic layer and, we prepared Co$\_$77/Cr$\_$20/Ta$_3$/Si doublelayer for perpendicular magnetic recording media which was promoted as next generation recording media on slide glass substrate. The thickness of magnetic layer and Underlayer were varied from 20 to 100 nm and 5 to 100 m, respectively. The surface morphology and crystal structure of the CoCrTa/Si film were examined with XRD and AFM. Prepared thin films showed improvement of dispersion angle of c-axis orientation Δ$\theta$$\_$50/ caused by inserting amorphous Si underlayer.

• Journal of Magnetics
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• 제16권4호
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• pp.403-407
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• 2011

Metal-insulator type, nano-granular soft magnetic films have been reviewed from the viewpoint of high frequency magnetic materials. The formation of nano-granular structure is related to the magnitude of heat of formation of intergranule materials. Variation of the ratio of granule phase to intergranule phase in the film is found to produce various characteristics in the magnetic properties of the film. The HRTEM observation reveals that neighboring granules in the film with above 60 at.% Co, contact at considerable points and the films show soft magnetic properties which are explainable in terms of the random anisotropy model for nano-crystalline materials. Addition of Ni group elements in Co-O based films enhances their anisotropy field up to 400 Oe and they exhibit excellent frequency response of permeability. Also, large electromagnetic noise suppression effect is demonstrated as one of their potential applications.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권4호
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• pp.149-155
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• 2002

This paper presents magnetic field analysis technology that uses a vector magnetic characteristic. Recently the magnetic material was found to be measurable using the vector quantity technique. Therefore considering the anisotropy of the magnetic material in the vector field analysis is necessary. The magnetic field analysis method, which is considered the anisotropy by combining the finite element method with the E&$S^2$ (Enokizono, Soda, and Shimoji) modeling, is applied to a permanent magnet motor model.