• Journal of Magnetics
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• v.10 no.2
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• pp.48-51
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• 2005

The spin transfer induced magnetization switching has been reported to occur in magnetic multilayer structures whose scope usually consists of one stack of ferromagnetic / non-ferromagnetic / ferromagnetic (F / N / F) materials. In this work, it is shown that: 1) Copper used as a buffer layer between the free Co and the Au cap-layer can clearly increase the probability to get the spin transfer induced magnetization switching in a simple spin valve Co 11 / Cu 6/ Co 2 (nm); 2) Furthermore, when Ruthenium is simultaneously applied as a buffer layer on the Si-substrate, the critical switching currents can be reduced by $30\%$, and the absolute resistance change delta R $[{\Delta}R]$ of that stack can be enlarged by $35\%$. The enhancement of the spin transfer induced magnetization switching can be ascribed to a lower local stress in the thin Co layer caused by a better lattice match between Co and Cu and the smoothening effect of Ru on the thick Co layer.

• Proceedings of the Korean Magnestics Society Conference
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• 2013.12a
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• pp.113-113
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• 2013

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.728-730
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• 2003

Bond lengths, harmonic vibrational frequencies and dissociation energies of TlAt are calculated at ab initio molecular orbital and density functional theory using effective spin-orbit operator and relativistic effective core potentials. Spin-orbit effects estimated from density functional theory are in good agreement with those from ab initio calculations, implying that density functional theory with effective core potentials can be an efficient and reliable methods for spin-orbit interactions. The estimated $R_e$, $ω_e$ and $D_e$ values are 2.937 ${\AA}$, 120 $cm^{-1}$, 1.96 eV for TlAt. Spin-orbit effects generally cause the bond contraction in Group 13 elements and the bond elongation in the Group 17 elements, and spin-orbit effects on Re of TlAt are almost cancelled out. The spinorbit effects on $D_e$ of TlAt are roughly the sum of spin-orbit effects on $D_e$ of the corresponding element hydrides. Electron correlations and spin-orbit effects are almost additive in the TlAt molecule.

• Journal of Magnetics
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• v.11 no.3
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• pp.108-110
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• 2006

We successfully enhanced the performance of a spin valve by inserting an ultra-thin layer of partially oxidized Fe in the pinned and free layers. With the exchange bias field kept large, the spin valve reached a GMR of 12%, which corresponded to a 55% increase in GMR when we compared it with that of spin valves without any inserted layer. The layer of partially oxidized Fe was more effective for improving the properties of the spin valve than the layer of partially oxidized $Co_{90}Fe_{10}$. Considering all the results, we can contribute the significant improvement to the combined effect of the modified local electronic structures at the Fe impurities and theenhanced spin-dependent reflections at the $\alpha-Fe_{2}O_{3} phase in the magnetic layer.

• Proceedings of the Korean Magnestics Society Conference
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• 2001.10a
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• pp.44-45
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• 2001

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.156.1-156.1
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• 2007

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.676-681
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• 2001

In this paper, the spin-up from rest to a state of solid-body rotation in a circular container with a slender rectangular obstacle on the bottom wall is analysed experimentally. We use a PIV method for the evolution of the free-surface flow. Laboratory experiments have been carried out for a variety of the obstacle height h(0, 5, 10 [mm]) and the liquid depth H(25, 50, 75, 100 [mm]). It was found that the spin-up time is crucially dependent on the obstacle height T. In the case of T=10[mm] the spin-up time is considerably shorter then the other cases.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.06a
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• pp.168-169
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• 2003

최근 세계적 주목을 받고 있는 spin FET 소자는 반도체에 주입된 spin 편향된 전자가 gate voltage(V$_{G}$)에 의해 반도체 계면에 유도된 전기장의 영향을 받아, Spin 세차운동을 하는 mechanism(Rashba 효과)이 근간을 이루고 있다. 작은 band gap을 가지는 반도체(narrow gap 반도체)는 작은 유효질량의 전자에 의해서 이러한 Rashba 효과를 크게 할 수 있어서, spin FET 구현을 위한 강력한 후보이며, 요즘 한창 연구되고 있는 주제이기도 하다. Rashba 효과가 저자기장 영역에서의 weak antilocalization효과로 나타남을 이용하여, 본 논문에서는 metal gate가 형성된 HgCdTe FET를 제작하여(FET1 시료, Fig. 1(a)참조), V$_{G}$에 따른 weak localization(WL) 및 weak antilocalization(WAL) 효과를 얻었다. 또한, Rashba 효과에 의한 spin 세차운동을 측정할 수 있는 소자(FET3 시료, Fig.1(b) 참조)를 제작하여 spin FET 구조에 대하여 연구하였다.

• Journal of Magnetics
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• v.14 no.2
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• pp.90-92
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• 2009

This study examined the current-induced spin wave excitation in asymmetric nanopillar junctions with a stack sequence of 20 nm Pt/10 nm Cu/7 nm NiFe/300 nm Cu, and a circular lateral dimension of 240 nm. An analysis of the magnetic and magnetotransport characteristics of the junction showed a possible spin transfer effect at this sample dimension when the magnetization was switched from a vortex state to another state. This finding is expected to help improve the understanding of the spin transfer torque phenomenon in nanopillar junctions.

• Journal of Magnetics
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• v.15 no.4
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• pp.185-189
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• 2010

Spin polarized tunneling through a hybrid tunnel barrier of a Spin filter (SF) based on a EuO ferro-magnetic semiconductor and an organic semiconductor (OSC) (rubrene in this case) was investigated. For quasi-magnetic tunnel junction (MTJ) structures, such as Co/rubrene/EuO/Al, we observed a strong spin filtering effect of the EuO layer exhibiting I-V curves with high spin polarization (P) of up to 99% measured at 4 K. However, a magnetoresistance (MR) value of 9% was obtained at 4.2 K. The low MR compared to the high P could be attributed to spin scattering caused by structural defects at the interface between the EuO and rubrene, due to nonstoichiometry in the EuO.