• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.30-31
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• 2002

100 Gbit/in$^2$ 이상의 자기기록밀도를 달성하기 위해서는 재생헤드로 사용되고 있는 스핀밸브의 자기저항비가 10% 이상을 가지면서 열적 특성이 우수해야 한다. 현재까지 연구되어진 스핀밸브 구조 중 NiO([,2,3], $\alpha$-Fe$_2$O$_3$[4]등의 산화물 반강자성 층을 사용한 스핀밸브의 경우 기본 스핀밸브 구조를 사용하고도 이미 20% 이상의 자기저항비를 달성하였다. 이러한 높은 자기저항비는 절연층인 산화물 반강자성층과 금속 자성층 계면에서 일어나는 전자의 스펙큘라 반사(specular reflection)로부터 기인한다고 보고하고 있다.[2] (중략)

• Journal of the Korean Magnetics Society
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• v.8 no.5
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• pp.282-287
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• 1998

Dependence of magnetoresistance on base pressure and deposition rates of each Fe, Co, Cu layers in the $Fe(50{\AA}/[Co(17{\AA})/Cu(24{\AA})]_20$ multilayer thin films, prepared by dc magnetron sputtering on Corning glass, were investigated. AFM analysis, X-ray diffraction analysis, vibrating sample magnetometer analysis, and magnetoresustance measurement (4-probe method) were performed. The multilayer films deposited under low base pressure increases magnetoresistance ratio by preventing oxidation. Annealing for the samples at a moderate temperature allowed larger textured grain with no loss in the periodicity. Magnetoresistance ratio of the annealed multilayers was increased due to the increase antiferromagnetically coupled fraction of the film after annealing. Optimization of deposition rate was greater than 1 $\AA$/s for Fe, and 2.8 $\AA$/s for Cu. Deposition rate of Co showed a tendency of increasing of magnetoresistance ratio due to the formation of flat magnetic layer in case of high deposition rate of Co.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.789-791
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• 2001

이전에 개발된 Magnetic Fluid Linear Pump는 자기 회로가 솔레노이드 형식으로 자기회로의 대부분이 공극이기 때문에 자기저항이 크다. 이런 문제로 인해서 Linear Pump의 자성유체에 영향을 주는 자기장이 크지 않고 펌핑 압력은 높지 않다. 따라서 본 논문에서는 Permalloy Yoke를 이용하여 Linear Pump를 소형화하고 자기 저항을 최소화함으로써 펌핑 압력을 향상시켰다. 또한 Linear Pump의 3D해석을 통하여 Yoke의 폭, 두께, 간격에 대한 최적 크기를 계산하였다.

• Journal of the Korean Magnetics Society
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• v.15 no.2
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• pp.61-66
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• 2005

In order to make submicron cell for spin-injection device, lift-off method using Pt stencil and wet etching was chosen. This approach allows batch fabrication of stencil substrate with electron-beam lithography. It simplifies the process between magnetic film stack deposition and final device testing, thus enabling rapid turnaround in sample fabrication. Submicron junctions with size of $200nm{\times}300nm$ and $500nm{\times}500nm$ 500 nm and pseudo spin valve structure of $CoFe(30{\AA})/Cu(100{\AA})/CoFe(120{\AA}$) was deposited into the nanojunctions. MR ratio was 0.8 and $1.1{\%}$, respectively and spin transfer effect was confirmed with critical current of $7.65{\times}10^7A/cm^2$.

• Journal of the Korean Magnetics Society
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• v.11 no.5
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• pp.202-210
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• 2001

Spin dependent tunneling (SDT) junction devices of Ta/NiFe/Ta/NiFe/FeMn/NiFe/AlOx/CoFe/NiFe/Al with in-situ naturally oxidized Al barrier were fabricated using ion beam deposition and dc sputtering in UHV chamber of 10$^{-9}$ Torr. The maximum tunneling magnetoresistance (TMR) and the product resistance by junction (R$_{j}$ A) are 16-17% and 50-60 $\Omega$${\mu}{\textrm}{m}$$^2$, respectively. The values of TMR and (R$_{j}$ A) with field annealing were slightly increased. The TMR and (R$_{j}$ A) dependence versus the junction area size was observed. These results were explained by using sheet resistance effect of bottom electrode and spin channel effects.

• Journal of the Korean Magnetics Society
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• v.8 no.1
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• pp.27-33
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• 1998

We have investigated tunneling magnetoresistance (TMR) properties of Fe/$Al_2O_3$/Co magnetic trilayer junctions sputtered on single-crystal Si (001) substrates. $Al_2O_3$ layers with thicknesses of 50~200 $\AA$ were deposited directly on the bottom ferromagnetic layer by a reactive rf sputtering. For comparsion, we prepared Pt/$Al_2O_3$/Pt tunnel junctions whose current-voltage (I-V) characteristics measured at 300 K indicated that reactively sputtered $Al_2O_3$ is a particularly good material for thin insulating barriers and allows us to form pinhole-free tunnel barriers. The magnetic tunnel junctions exhibit changes of tunnel resistance of about 0.1% at 300 K with an applied magnetic field and it was found that most junctions with Co as a top electrode have rather good I-V and TMR characteristics compared to those with Fe as a electrode. These results were discussed in relation to interfacial on the basis of those for Pt/$Al_2O_3$/Pt.

• Journal of Sensor Science and Technology
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• v.1 no.1
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• pp.23-34
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• 1992

In order to fabricate magnetoresistive sensor, Fe-Ni and Co-Ni alleys were evaporated on the slide glass and the silicon wafers. Saturation magnetic induction($B_{s}$), coercive field strength($H_{c}$) and magnetoresistance were measured for fabricated samples. The evaporated Fe-Ni thin films show that the saturation magnetic induction was 0.65 T, and coercive field strength was 0.379 A/cm, and this value was changed to 0.370 A/cm(//), 0.390 A/cm(${\bot}$), respectively after magnetic annealing. For the measurement of coercive field strength, magnetizing frequency of 1 kHz was used. For the fabricated sensor element, the change of magnetoresistance (${\Delta}R/R$) was excessively unstable due to oxidation in the process of fabrication. The evaporated Co-Ni alloy thin films show that saturation magnetic induction was 0.66 T, and coercive field strengthes were 5.895 A/cm(//), 5.898 A/cm(${\bot}$), respectively, after magnetic annelaing. The change of magnetoresistance(${\Delta}R/R$) was $3.6{\sim}3.7%$ of which value was excessively stable to room temperature. Fe-Ni thin film could have many problems due to large affinity in the process of fabrication of magnetoresistance sensor, but Co-Ni thin film could be a suitable material for fabrication of magnetoresistance sensor, because of its small affinity and definite magnetoresistance effects.

• Journal of the Korean Magnetics Society
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• v.8 no.5
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• pp.288-294
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• 1998

Effect of degree of intermixing at the Ta/NiFe interface induced by varying applied substrate bias voltage during NiFe free layer deposition on change of magnetoresistance in Substrate/Ta/NiFe/Cu/NiFe/FeMn/Ta spin valve multilayers was investigated. It was found that the optimum NiFe free layer thickness showing a maximum MR increase with increasing the bias voltage. The increase of the optimum thickness was due to the increase of the intermixed layer thickness with a bias voltage. The weak ferromagnetic or non ferromagnetic intermixed layer plays as a spin-independent scattering region and does not contribute on spin-dependent scattering. The existence of the intermixed layer was proved by the means of electrical resistivity and magnetization changes. In the present study, the optimum "effective" free layer thickness which gives the highest MR ratio was a constant independent of the magnitude of the bias voltage we have used.have used.

• Proceedings of the Korean Magnestics Society Conference
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• 2011.06a
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• pp.138-139
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• 2011

• Proceedings of the Korean Magnestics Society Conference
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• 1999.10a
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• pp.116-117
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• 1999