• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.129.2-129.2
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• 2007

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.134.1-134.1
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• 2007

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 춘계연구발표회 논문개요집
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• pp.44-45
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• 2002

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2004년도 하계학술연구발표회 논문개요집
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• pp.148-149
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• 2004

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2004년도 하계학술연구발표회 논문개요집
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• pp.150-151
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• 2004

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2001년도 추계연구발표회 논문개요집
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• pp.58-59
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• 2001

• Journal of Magnetics
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• 제6권3호
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• pp.90-93
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• 2001

Co/$Al_O_3$/NiFe and CO/$Al_O_3$/Co tunnel junctions were fabricated by a radio frequency magnetron sputtering at room temperature with hard mask on glass and $4^{\circ}$ tilt cut Si (111) substrates. The barrier layer was formed through two steps. After the Al layer was deposited, it was oxidized in the chamber of a reactive ion etching system (RIE) with $O_2$plasma at various conditions. The dependence of the TMR value and junction resistance on the thickness of Al layer (before oxidation) and oxidation parameters were investigated. Magnetoresistance value of 7% at room temperature was obtained by optimizing the Al layer thickness and oxidation conditions. Circular shape junctions on $4^{\circ}$tilt cut Si (111) substrate showed 4% magnetoresistance. Photovoltaic energy conversion effect was observed with the cross-strip geometry junctions on Si substrate.

• Journal of Magnetics
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• 제14권1호
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• pp.11-14
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• 2009

We investigated the I-V curves and differential tunneling conductance of two, CoFeB/MgO/CoFeB-based, magnetic tunnel junctions (MTJs): one with a low tunneling magnetoresistance (TMR; 22%) and the other with a high TMR (352%). This huge TMR difference was achieved by different MgO sputter conditions rather than by different annealing or deposition temperature. In addition to the TMR difference, the junction resistances were much higher in the low-TMR MTJ than in the high-TMR MTJ. The low-TMR MTJ showed a clear parabolic behavior in the dI/dV-V curve. This high resistance and parabolic behavior were well explained by the Simmons' simple barrier model. However, the tunneling properties of the high-TMR MTJ could not be explained by this model. The characteristic tunneling properties of the high-TMR MTJ were a relatively low junction resistance, a linear relation in the I-V curve, and conduction dips in the differential tunneling conductance. We explained these features by applying the coherent tunneling model.

• 한국자기학회지
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• 제19권1호
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• pp.1-4
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• 2009

미소자기학 모델을 이용하여, 인위적 반강자성체에서 자화의 시도주파수에 대한 연구를 진행하였다. 다양한 일축 자기이방성, 패턴 구조 및 패턴된 시편의 에너지 장벽 크기에 대해 시도주파수를 조사하였다. 시편의 부피가 동일한 경우, 인위적 반강자성체를 구성하는 두 자성층의 결합 자기장에 따라 시도주파수가 변화하는 것을 관측하였다. 또한 에너지 장벽의 크기가 동일한 경우에도, 일축 자기이방성에 따라 시도주파수가 매우 크게 변하는 사실을 알게 되었다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2013년도 임시총회 및 하계학술연구발표회
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• pp.18-18
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• 2013

A FeRh alloy is a well-known efficient magnetocaloric material and some experimental and theoretical studies of bulk FeRh have been reported already by several groups. In this study we report first-principles calculations on magnetic properties of different thickness FeRh thin films in order to investigate the possibility to enhance further the magnetocaloric efficiency. We used Vienna Ab-initio Simulation Package (VASP) code. We found that the FeRh thin films have quite different magnetic properties from the bulk when the thickness is thinner than 6-atomic-layers. While bulk FeRh has a G-type antiferromagnetic (AFM) state, thin films which are thinner than 6-atomic-layers have an A-type AFM state or a ferromagnetic(FM) state. We will discuss possibility of magnetic phase transitions of the FeRh thin films in the view point of a magnetocaloric effect. And we found 4-, 5-, 6-layers films with Fe surface and 7-layers film with Rh surface are FM and they have dozens eV magnetocrystalline anisotropy (MCA) energy. MCA energy leads to determine energy barrier when magnetic states are changed by external magnetic field.