• Journal of the Korean Magnetics Society
• /
• v.6 no.5
• /
• pp.334-339
• /
• 1996

In order to investigate the influence of the magnetic paticle size and its properties on the particulate magnetic material, we evaluated the dispersion of magnetic particles and the electromagnetic properties in magnetic tape made from the magnetic paints by use of each magnetic particles witch were different from particle size and its propertis. The dispersion of magnetic particles depends on the surface chemical properties rather than particle size. As particle size is smaller, the packing ratio of magnetic particle and the magnetic flux density in tape increase. The output levels in playing back of tape incerase in wide frequency range from 315 Hz to 10 kHz and the noises decrease. It is very important to choose the size, the shape, the surface chemical properties and the magnetic properties of the magnetic particle in producing the high quality magnetic tape.

• Journal of the Korean Magnetics Society
• /
• v.21 no.4
• /
• pp.141-146
• /
• 2011

We will introduce the surface magneto-optic Kerr effect (SMOKE), which is one of the most helpful experimental methods in the area of surface magnetism for the last two decades. The basic magnetic characteristics of magnetic thin film is the most essential part for the further understanding and application. For example, the possibility of the realization of ferromagnetism for a single layer of iron, its Curie temperature far below that of bulk iron, and the direction of easy axis are the fundamental questions for the spintronic application. SMOKE is an efficient method to answer for the questions above.

• Journal of the Korean Magnetics Society
• /
• v.17 no.3
• /
• pp.109-113
• /
• 2007

We investigated the magnetic properties of VRu(001) surface by using the all electron full-potenial linearized augmented planewave (FLAPW) energy band method within the GGA. We consider two different configurations, V and Ru surface layers, respectively. The V atoms in surface layer was calculated to have large magnetic moment of $1.71_{{\mu}_B}$ while the Ru surface layer to have nearly nonmagnetic state. The calculated spin-polarized density of states. spin density contour, and charge density were discussed in relation to the magnetic properties of VRu(001) surface.

• Korean Journal of Crystallography
• /
• v.20 no.1
• /
• pp.9-14
• /
• 2009

직충돌 이온산란 분광법(ICISS: Impact Collision Ion Scattering Spectroscopy)을 이용한 고체표면 해석의 마지막 개설로서 금속 표면에 대한 연구를 소개하기로 한다. 금속은 도체이기 때문에 전하 축적을 방지하려는 별도의 장치가 필요 없다. 또한 결정구조가 간단하여 금속재료 자체보다는 표면의 흡착구조 및 반응, 박막 구조 등과 같은 분야에서 ISS를 이용하고 있다. 세라믹이나 반도체와 구별되는 응용 분야로서는 첫째 금속의 높은 표면 반응성을 이용하는 촉매와 같은 분야에 있어서 표면에서 일어나는 반응을 추적하기 위한 수단으로 사용된다. 둘째 표면 용융 현상을 표면 원자의 위치 결정을 통하여 연구할 수 있다. 마지막으로 자성재료의 표면 자성 특성을 스핀분극 ISS를 이용하여 접근할 수 있다. 이상과 같은 금속 표면물성 분야에 대하여 ICISS를 적용한 연구 사례를 소개하고자 한다.

• Journal of the Korean Magnetics Society
• /
• v.19 no.5
• /
• pp.165-170
• /
• 2009

It is well-known that a meta-stable fcc bulk Fe has an antiferromagnetic (AFM) ground state and could be synthesized by growing Fe on a proper fcc metal substrate. In this study magnetism of Fe monolayers on nonmagnetic fcc transition metal (Cu, Rh, Pd, and Ag) (001) surfaces has been investigated using the all-electron full-potential linearized augmented plane wave method. The Fe monolayers on Rh(001) and Pd(001) surfaces were calculated to be stabilized in an AFM state, whereas the Fe monlayers on Cu(001) and Ag(001) surfaces are stabilized in a ferromagnetic (FM) state. Noting that Cu and Ag have the smallest and largest lattice constants and the fcc bulk Fe with a larger lattice constant is getting stabilized in a ferromagnetic state, it is unexpectable and interesting. The calculated magnetic moments of the Fe atoms on Cu, Rh, Pd, and Ag(001) surfaces are 2.811, 2.945, 2.987, and 2.990 $_{{\mu}B}$ in FM states and 2.624, 2.879, 2.922, and 3.001 $_{{\mu}B}$ in AFM states.

• Journal of the Korean Magnetics Society
• /
• v.25 no.5
• /
• pp.139-143
• /
• 2015

The surface magnetism of the CsCl structured Co binary compounds, CoX (X = Ti, V, Nb) (001) surface was studied with the calculated electronic structure data obtained by the full-potential linearized augmented plane-wave (FLAPW) method. The magnetic moment of the surface Co atom of the Co-terminated CoTi(001) system was $1.19{\mu}_B$, which is enhanced compared with that of the Co atom in the center layer. The magnetic moment of the surface V atom in the V terminated the CoV(001) system was $1.64{\mu}_B$, which is more than twice of the center layered V atom. The magnetic moment of surface Co atom in the Co terminated CoV(001) system has the value of $1.34{\mu}_B$, little bit smaller than the bulk value. The magnetism was disappeared in the Co terminated CoNb(001) system, and the magnetic moment of the surface Nb atom in the Nb terminated CoNb(001) system was $0.26{\mu}_B$ which is little bit decreased compared to the center layer value.

• Journal of the Korean Magnetics Society
• /
• v.10 no.2
• /
• pp.86-92
• /
• 2000

The spin wave absorption spectra are obtained by a simultaneous solution of the Maxwell equation and the Gilbert equation considering the boundary condition of electromagnetic wave and magnetization in the film surfaces. The physical parameters that influence the absorption energy are thickness, exchange stiffness constant, surface magnetic anisotropy, magnetization. damping factor, electric resistivity of the thin film. We investigated how these parameters affect the resonance field, the linewidth and the intensity of the spin wave spectrum.

• Journal of the Korean Magnetics Society
• /
• v.22 no.5
• /
• pp.183-187
• /
• 2012

In this paper, fluid movement of magnetic fluid which has free surface is investigated in a container subjected to a horizontal oscillation. Here, the vertical magnetic field is applied from the bottom of this container. The experiment is performed on the magnetic fluid in a rectangular and a cylindrical container and the effects of magnetic force exerted on the magnetic fluid are investigated on the resonance frequency and liquid surface displacement. The increase of magnetic field affects on the maximum resonance point and the liquid surface displacement. In result, it changes the amplitude of the surface wave and the period of sloshing fluid movement.

• Journal of Wetlands Research
• /
• v.21 no.2
• /
• pp.152-156
• /
• 2019

The removal property of magnetic zeolite for the adsorption of aqueous ammonium ion was examined in this work. The surface modified magnetic zeolite was produced by hydrothermal synthesis. The complex of zeolite and $Fe_3O_4$ was established by the observation of SEM and XRD analysis and less than 12.6% of $Fe_3O_4$ content in magnetic zeolite was observed in the form of $Fe_3O_4$ particles. The optimum pH of adsorption was shown around 8 and the maximum adsorption linearly decreased with the increase of $Fe_3O_4$ content. The adsorption isotherm for aqueous ammonium ion was approximated by Langmuir equation. The developed surface modified magnetic zeolite adsorbent was recommended to control the nitrogen pollution for wetland environment system.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.28 no.5
• /
• pp.395-400
• /
• 2008

Alternating magnetic field was used for detection of surface flaws on nonmagnetic and magnetic metallic specimens. The nondestructive sensor probe was composed of the planar coil with inductive magnetic thin film yoke as a sensing component and a single straight typed exciting coil. The planar inductive coil sensor with magnetic yoke was fabricated by sputtering, electroplating, dry etching and photolithography process. The alternative currents with the range of 0.1A to 1.0A (0.7 MHz to 1.8 MHz) were applied to the exciting coil. The specimens were prepared with the slit shaped artificial surface flaws (minimum depth and width; 0.5 mm) on metallic plate (Al; nonmagnetic metal and FeC; magnetic metal). The detected signal for the positions and shapes of surface flaws on specimens were obtained with high sensitivity and high signal to ratio. The measured output signals by the non-contacted scanning on surface of FeC specimen with micron-sized crack were converted to the images of the flaws. And these results were compared with the optical images, respectively.