• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2338-2340
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• 2012

The spin exchange parameters of $VOSb_2O_4$ were evaluated by performing energy-mapping analysis based on density functional calculations. The spin exchange interaction between the nearest-neighbor $V^{4+}$ ions is strongly antiferromagnetic while other interactions are negligible. Thus, the magnetic structure of $VOSb_2O_4$ is best described by a spin-1/2 Heisenberg antiferromagnetic chain with no spin frustration.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1665-1668
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• 2010

The spin exchange interactions of $(VO)_2(H_2O){O_3P-(CH_2)_3-PO_3}{\cdot}2H_2O$ were examined by spin dimer analysis based on extended Huckel tight binding method. The strongest spin exchange interaction occurs through the super-superexchange path $J_2$ and the second strongest spin exchange interaction occurs through the superexchange interaction path $J_1$. There are two strongly interacting spin exchange paths in $(VO)_2(H_2O){O_3P-(CH_2)_3-PO_3}{\cdot}2H_2O$. Therefore, magnetic susceptibility curve of $(VO)_2(H_2O){O_3P-(CH_2)_3-PO_3}{\cdot}2H_2O$ can be well reproduced by an alternating onedimensional antiferromagnetic chain model rather than an isolated spin dimer model.

• Journal of Magnetics
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• v.14 no.4
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• pp.168-171
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• 2009

We propose a new type of spin torque nano-oscillator structure with an exchange- biased free rotating layer. The proposed spin torque nano-oscillator consists of a fixed layer and a free rotating layer with an additional anti-ferromagnetic layer, which leads to an exchange bias in the free rotating layer. The spin dynamics of the exchange-biased free rotating layer can be described as an additional exchange field because the exchange bias manifests itself by the existance of a finite exchange bias field. The exchange bias field plays a similar role to that of a finite external field. Hence, microwave generation can be achieved without an external field in the proposed structure.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.467-471
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• 2011

Spin exchange interactions of $(C_2N_2H_{10})[Fe(HPO_3)F_3]$ were examined by performing a spin dimer analysis based on extended Huckel tight binding method and a mapping analysis based on first principles density functional theory. Spin exchange interactions occur through the super-superexchange paths $J_1$ and $J_2$ in $(C_2N_2H_{10})[Fe(HPO_3)F_3]$. In the super-superexchange path $J_2$ magnetic orbital interactions between eg-block levels are much stronger than those from $t_{2g}$-block levels. Both electronic structure calculations show that the spin exchange interaction through the super-superexchange path $J_2$ is much stronger than that of $J_1$.

• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.122-126
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• 2008

The magnetic properties of the organic/inorganic hybrid copper-methylenediphosphonate, Cu2(O3PCH2PO3) were examined by performing the spin dimer analysis based on the extended Hckel tight binding method. In Cu2(O3PCH2PO3) the CuO3 chains made up of edge-sharing CuO5 square pyramidal units are inter-linked by O-P-O bridges. The Cu-O-Cu superexchange interactions of the CuO3 chains are negligibly weak compared with the Cu-O…O-Cu super-superexchange interactions that occur between the CuO3 chains. The spin exchange interactions of Cu2(O3PCH2PO3) are dominated by three super-superexchange interactions, which leads to a three-dimensional antiferromagnetic spin lattice. The strongest spin exchange interactions form isolated spin dimers, which suggests that, to a first approximation, the magnetic properties can be described in terms of an isolated spin dimer model.

• Journal of Distribution Science
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• v.21 no.12
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• pp.83-89
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• 2023

Purpose: Research on spin-off and treasury stock is necessary because the market has realized that this can be utilized for major shareholder private interest. Considering the unique characteristic of a spin-off and treasury stock in the Korean stock market, this study contributes to the literature by examining the effects on shareholder value in the Korean distribution industry. Research design, data, and methodology: The present study investigates literature, analyst reports, and news articles to examine the spin-off process and analyze how treasury stock magic happens. Results: Setting the exchange ratio favoring Spin-Co in the spin-off is the leading cause for reducing the minor shareholders' value. Moreover, treating treasury stock as an asset is also problematic, allowing the allocation of Spin-Co shares. This leads to an increase in the major shareholder controls of Spin-Co without any contribution from the major shareholders. Therefore, the exchange ratio should be calculated reasonably, and treasury stock from the stock repurchase should be treated as stock retirement. Conclusion: By analyzing the spin-off and how treasury stock magic occurs, this study provides recommendations to improve shareholder value. Moreover, it contributes to the maturation of the Korean capital market by promoting a discussion on the revision of spin-off and treasury stock.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.240.1-240.1
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• 2008

• Journal of Magnetics
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• v.7 no.3
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• pp.80-93
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• 2002

The role of magnetic anisotropy of the antiferromagnetic layer on the magnetization process of exchange coupled polycrystalline ferromagnetidantiferromagnetic bilayers is discussed. In order to elucidate the magnetic torque response of Ni-Fe/Mn-Ir bilayers, the single spin ensemble model is newly introduced, taking into account the two-dimensionally random distribution of the magnetic anisotropy axes of the antiferromagnetic grains. The mechanism of the reversible inducement of the exchange anisotropy along desirable directions by field cooling procedure is successfully explained with the new model. Unidirectional anisotropy constant, J$k$, of polycrystalline Ni-Fe/Mn-Ir and Co-Fe/Mn-Ir bilayers is investigated as functions of the chemical composition of both the ferromagnetic layer and the antiferromagnetic layer. The effects of microstructure and surface modification of the antiferromagnetic layer on JK are also discussed. As a notable result, an extra large value of J$k$, which exceeds 0.5 erg/cm$^2$, is obtained for $Co_{70}Fe_{30}Mn_{75}Ir_{25}$ bilayer with the ultra-thin (50${\AA}$∼100${\AA}$) Mn-Ir layer. The exchange anisotropy of $Co_{70}Fe_{30}$ 40 ${\AA}/Mn_{75}Ir_{25}$ 100 ${\AA}$ bilayer is stable for thermal annealing up to $400{^{\circ}C}$, which is sufficiently high for the application of spin valve magnetoresistive devices.

• Journal of the Korean Magnetic Resonance Society
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• v.11 no.1
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• pp.1-9
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• 2007

An unequal site exchanging system induced by restricted rotation of 9-methyl group in 1,8-dichloro-9-triptycene has been studied by spin-lattice relaxation and 2D-EXSY experiments. The exchange rate obtained from relaxation studies is very well coincident to the result of line shape analysis, and the difference of the relaxation times ($T_1$) in two different sites has an important role to analyze 2D-EXSY experimental data.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.73-82
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• 1998

The exchange anisotropy is the unidirectional magnetic anisotropy which comes from exchange interaction between antiferromagnetic layer and ferromagnetic layer. The application of this phenomenon to MR read head and spin-valve type GMR (Giant Magnetoresistance) head has been studied extensively. In our study, we intended to apply exchange anisotropy of NiO/NiFe bilayer to spin-valve type GMR element. Above all, we studied the exchange anisotropy of NiO/NiFe bilayer, and focused especially on the effect of NiO deposition condition. And we found that Ar pressure during NiO deposition was crucial factor for the exchange anisotropy of NiO/NiFe bilayer. The lower the Ar pressure is, the better the characteristics of exhange anisotropy is. Then, we applied this optimum condition of NiO/NiFe bilayer to spin-valve type GMR element. Finally we got spin-valve type GMR element which had 3.6 % MR ratio, 16 Oe switching field, and 0.25 %/Oe sensitivity.