• Proceedings of the Optical Society of Korea Conference
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• 1988.06a
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• pp.127-131
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• 1988

In order to clarify the origin of perpendicular anisotropy in thermally evaporated TbFeCo amorphous thin films, we have investigated the effects of deposition angle on magnetic Kerr hysteresis loop, perpendicular magnetic anisotropy and internal stress depend strongly on the deposition angle and above a threshold value(30$^{\circ}$), the perpendicular anisotropy disapperars and the in-plane anisotropy appears. The measurement of internal stress is the major contribution to the perpendicular anisotropy. The measurements of Kerr hysteresis loops in the polar and the longitudinal directions show that as the deposition angle increases the polar kerr hystresis loop deteriorates while the longitudinal Kerr hystersis loop becomes prominent.

• Journal of Magnetics
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• v.9 no.2
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• pp.47-51
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• 2004

Giant magneto-impedance (GMI) effect in zero-magnetostrictive Co-based amorphous ribbons samples in their as-quenched and stress-released states as well as with intentionally induced magnetic anisotropy were investigated. Magnetic and impedance properties of the samples exhibiting different anisotropy were compared and the optimum operation conditions for the studied samples from the view-point of their utilization as a sensor element have been determined. A design of a model of magnetic field sensor and characteristics of the constructed prototype are presented.

• Journal of Biomedical Engineering Research
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• v.15 no.4
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• pp.401-406
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• 1994

A magnetic resonance neurography technique for exclusive imaging of nerve networks is proposed. In the proposed technique, the anisotropy of diffusion coefficients of the molecules inside nerve cells was utilized to effectively suppress the magnetic resonance signal radiating from ones other than nerve tissues. Two images were obtained with diffusionweighting magnetic field gradients applied in the parallel and perpendicular directions with respect to the nerve orientation. One image was then subtract- ted from the other to form the neurogram. Experimentally obtained neurograms of the squld are presented.

• Journal of Magnetics
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• v.9 no.4
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• pp.121-124
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• 2004

NiO thickness dependences of perpendicular magnetic anisotropy (PMA) in the $NiO/[CoFe/Pt]_5$ multilayers for exchange biasing and $[CoFe/Pt]_4/Pt/[CoFe/Pt]_4$ for interlayer exchange coupling were investigated. Perpendicular magnetization curve was obtained by out-of-plane extraordinary Hall measurement. Magnetic force microscopy (MFM) has been used for the investigation of magnetic domains on thin films. We confirmed that the interlayer exchange coupling (IEC) as a function of NiO thickness at room temperature existed with a period of two monolayers.

• Journal of Magnetics
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• v.4 no.2
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• pp.65-68
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• 1999

The M-type barium ferrite ($BaFe_{12}O_{19}$) is well known magnetic material to be used as a permanent magnet due to its strong uniaxial anisotropy. The substitution of nonmagnetic $Ti^{+4}$ and magnetically weak $Co+^2ion for Fe^{+3}$ to its strong uniaxial anisotropy. The substitution of nonmagnetic $Ti^{+4}$ and magnetically weak $Co+^2ion for Fe^{+3}$ sublattices reduces the uniaxial anisotropy and those compounds open a new application field of noise suppressor at high frequencies. In this study, the magnetic and microwave absorbing properties are investigated in Ti-and Co-substituted barium ferrites ($BaFe_{12-2X} Ti_XCo_XO_{19}$). The saturated magnetization decreases linearly with the substitution of Ti and Co. The rapid drop in coercive force is observed with Ti and Co substitution upto x=1.2. The magnetic permeability spectrum shows the natural magnetic resonance in the specimens with small coercive force and large attenuation of microwave is predicted in those specimens at high frequencies (above 4 GHz).

• Journal of the Korean Magnetics Society
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• v.4 no.2
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• pp.179-183
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• 1994

A high efficiency small electromagnet (22 mm air gap and $40{\times}25mm^{2}$ core's cross section) suitable for measuring magnetostriction and magnetic anisotropy was biult. The magnet could be minaturized by reducing the measuring space and time. The excitation current of the electromagnet was supplied for only a few second of measuring time. Cooling system of the electromagnet could be eliminated since the dissipation energy was very small. An 0.5 T magnetic field was generated with 180 W power consumption. The values of magnetostriction and magnetic anisotropy were measured with a very sensitive capacitance cell with resolution of $10^{-8}$ and 1 nJ. The torque was calibrated using a soft magnetic ribbon's shape anisotropy.

• Journal of the Korean Magnetics Society
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• v.4 no.3
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• pp.256-262
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• 1994

$200{\AA}$ thick Co/Pd multilayered thin films were fabricated by sputtering. Two thicknesses of cobalt sublayer, $2{\AA}$ and $4{\AA}$ were chosen and the effects of sputtering pressure on the perpendicular magnetic anisotropy were investigated. It has been found that the optimum pressure for maximum perpendicular magnetic anisotropy(PMA) existed and the pressure for maximum PMA was lower for the multilayer with $2{\AA}$ cobalt layer than that with $4{\AA}$ cobalt thickness. As the sputtering gas presssure increased, domain wall motion with magnetization became difficult and the predominant mode of magnetization reversal changed from domain wall motion to magnetic moment rotation. It turned out that the perpendicular magnetic anisotropy was higher in case of $2{\AA}$ cobalt thickness than $4{\AA}$ cobait thickness.

• Journal of the Korean Magnetics Society
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• v.2 no.3
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• pp.251-256
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• 1992

Artificial superlattices of Co/Pd were prepared by RF magnetron sputtering Multilayered structure and compositional modulation were analyzed with a side angle x-ray diffractometer. It has been found that expansion of Co lattice occured in this artificial superlattice due to the lattice mismatch between Co and Pd. Perpendicular magnetic anisotropy could be observed when the Co layer thickness became less than 8${\AA}$ and maximum coercivity of 2350 Oe could be obtained in [Co(2.5 ${\AA}$)/Pd(9.3 ${\AA})]_{50}$/Pd$(200\;{\AA})$ with a perfect squareness of magnetic hysteresis loop. Characteristic of perpendicular magnetic anisotropy in Co/Pd superlattices could be related to the expansion of Co lattice caused by Pd layer and it turned out that as the thickness of Pd layer increased, perpendicular magnetic anisotropy increased. The interface anisotropy energy and volume anisotropy energy were calculated to be 0.29 ergs/$cm^2$ and -$6.9{\times}10^6$ ergs/$cm^3$ respectively, which are consistent with the values reported elsewhere.

• Journal of the Korean Magnetics Society
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• v.5 no.6
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• pp.921-927
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• 1995

The micro particle,s shapes of the magnetic films obtained by electrode position of Iron ions and Cobalt-Iron mixed ions in aluminum anodic oxidized films are dependent on the size of particle diameter. When the diameter of deposited particles is larger than $300\AA$, the film plane anisotropy caused by bottom extremity increases, and the crystalization orientation of FeC deposited unusually in the part of the bottom extremities affects on the coercive force Hc and the magnetic anisotropy energy Ku. It was confirmed that the shape anisotropy of particle affects on the both Hc and Ku because the FeC did not deposit in the Iron deposited samples entirely, but in the Cobalt-Iron alloy deposited samples, the effects by the very strong crystalization orientation of the FeC is larger than that of the shape anisotropy. From these results, the Cobalt-Iron alloyed films could switchover the film plane magnetic anisotropy to the perpendicular magnetic anisotropy energy by using the constrainting method of FeC deposition with Cu deposition instead of Cobalt-Iron alloy in the bottom extremities.

• Journal of the Korean Magnetics Society
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• v.1 no.1
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• pp.30-36
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• 1991

A measurement system for magnetic anisotropy was built. The torque acting on the disc or sperical samples placed in uniform magnetic field was detected with a capacitive transducer which is connected with a transformer ratio-arm bridge. The output of the bridge was amplified with a lock-in amplifier. The cubic anisotropy constant for (100) of 3% Si-Fe was $3.3{\times}10^{4}\;J/m^{3}$. The calibration for the system was carried out with the shape anisotropy of a thin Ni wire.