• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.4
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• pp.160-165
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• 2001

The effects of various metals on Field Aided Lateral Crystallization (FALC) behaviors of amorphous silicon (a-Si) were investigated. Under an influence of electric field, metals such s Cu, Ni and Co were found to fasten the lateral crystallization toward a metal-free region, exhibiting a typical FALC behavior while the lateral crystallization of a-Si was not obvious for Pd. However, Au, Al and Cr did not induce the lateral crystallization of a-Si in metal-free region. Such phenomenological differences in various metals were studied in terms of dominant diffusing species (DDS) in the reaction between metal and Si. It was judged that the applied electric field enhanced the crystallization velocity by accelerating the diffusion of metal atoms since the occurrence of lateral crystallization would be strongly dependent on the diffusion of metal atoms than that of Si atoms. Therefore, it was concluded that he only metal-dominant diffusing species in the reaction between metal and Si results in the crystallization of a-Si in metal-free region.

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.634-640
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• 2005

The reaction of cis-[Cr([14]-decane)(OH$_2)_2]^+$ ([14]-decane = rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-teraazacyclotetradecane) with auxiliary ligands {$L_a$ = citrate(cit)} leads to a new dimeric complex cis-[{Cr([14]-decane)($\mu$-cit)}$_2](ClO_4)_2$. This binuclear complex has been structurally characterized by a combination of elemental analysis, conductivity, IR and Vis spectroscopy, mass spectrometry, and X-ray crystallography. Analysis of the crystal structure of cis-[{Cr([14]-decane)($\mu$-cit)})($_2]^+$ reveals that each chromium has a distorted octahedral coordination environment and citrato ligands are monodentate to the two chromium atoms via the carboxyl groups. For dimeric complex the bridging geometry is as follows: Cr$\ldots$Cr = 7.361 $\AA$; Cr-O(average) = 1.958 (8) $\AA$; Cr-N range = 2.108 (9)-2.147(9) $\AA$; N(1)-Cr-N(3) (equatorial position) = 98.0(4)$^{\circ}$; N(2)-Cr-N(4) (axial position) = 166.4(4)$^{\circ}$; O(1)-Cr-N(2) = 98.1(4)$^{\circ}$; O(3)-Cr-N(4) = 96.6(3)$^{\circ}$; O(1)-Cr-O(3) = 90.4$^{\circ}$. The FAB mass spectrum of the dimeric complex displays peak due to the molecular ions cis-[{Cr([14]-decane)($\mu$-cit)})($_2]^+$ at m/z 1053.

• Journal of the Korean Magnetics Society
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• v.15 no.5
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• pp.257-260
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• 2005

We investigated the half-metallicity and magnetism for the zinc-blende CrS(001) surfaces by use of the full-potential linearized augmented plane wave (FLAPW) method. We considered two-types of (001) surfaces terminated by Cr (Cr-Term) and S (S-Term) atoms, respectively. From the calculated layer-by-layer density of states, it is found that both of the systems retain the half-metallicity at the (001) surfaces. The calculated magnetic moment ($4.07\;{\mu}_B$) for the CrS(S) atom in Cr-Term is enhanced considerably compared to the bulk value ($3.61\;{\mu}_B$) while that ($3.15\;{\mu}_B$) of the Cr(S-1) in S-Term is much reduced.

• Journal of the Korean Magnetics Society
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• v.25 no.2
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• pp.31-38
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• 2015

Recently, a first-principles study led to a prediction that quaternary Heusler compounds, CoFeCrZ (Z = Ga, Ge) are excellent half-metallic ferromagnets. In this study, we investigate the electronic and the magnetic properties at the (001) surfaces of CoFeCrGa and CoFeCrGe by means of the full-potential linearized augmented plane wave (FLAPW) method within generalized gradient approximation. We considered two types of surface termination: CoFe-terminated and CrZ-terminated surfaces, Z being either Ga or Ge. From the calculated total magnetic moments and the local density of states, we found that half-metallicity is not preserved for all the surfaces. But the calculated atomic density of states showed that CrGa-terminated surface of the CoFeCrGa is almost half-metallic. The magnetic moment of the Co, Fe, or Cr atoms at the surface or subsurface layers in each system had very different values.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.167-168
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• 2012

Films of CrN, $Cr_{40}Zr_9N$, and $Cr_{31}Zr_{16}N$ were deposited on a steel substrate by closed field unbalanced magnetron sputtering, and their oxidation behaviors at $700^{\circ}C$ and $800^{\circ}C$ for up to 60h in air were investigated. All the deposited films were composed of the CrN phase. Zirconium atoms in $Cr_{40}Zr_9N$ and $Cr_{31}Zr_{16}N$ films partially dissolved in the CrN phase. They advantageously refined the columnar structure, reduced the surface roughness, and increased the microhardness. The CrN film displayed relatively good oxidation resistance, owing to the formation of the highly protective $Cr_2O_3$ on its surface. The $Cr_{40}Zr_9N$ and $Cr_{31}Zr_{16}N$ films oxidized to $Cr_2O_3$ as the major phase and ${\alpha}-ZrO_2$ as the minor one. They oxidized primarily by the inward transport of oxygen. The addition of Zr could not increase the oxidation resistance of the CrN film, because the formed $ZrO_2$ that was intermixed in the $Cr_2O_3$-rich oxide layer was oxygen permeable, and developed the compressive stress in the oxide scale owing to the volume expansion during its formation.

• Journal of Photoscience
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• v.11 no.1
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• pp.19-23
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• 2004

The sharp-line absorption spectrum of microcrystalline samples of cis-[Cr(cycb)$Cl_2$]Cl (cycb=rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) has been measured between 13000 and $16000 cm^{-1}$ at temperatures down to 5K. The 77K emission and excitation spectra, and 298 K infrared and visible absorption spectra have also been measured. The nine electronic bands due to spin-allowed and spin-forbidden transitions were assigned. Using the observed transitions, a ligand field analysis has been performed to probe the ligand field properties of coordinated atoms in the title chromium(III) complex. The zero-phonon line in the sharp-line absorption spectrum splits into two components by $240 cm^{-1}$ , and the $large ^2$$_E{g}$ splitting can be reproduced by the modem ligand field theory. It is confirmed that nitrogen atoms of the macrocyclic cycb ligand have a strong $\sigma$-donor character, but chloride ligand has weak $\sigma$- nd $\pi$-donor properties toward chromium(III) ion.n.

• Journal of the Korean Magnetics Society
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• v.19 no.5
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• pp.157-160
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• 2009

We have studied electronic structures and magnetic properties of one dimensional Ge chain nanoclusters using OpenMX method based on densty functional method. The calculation results show the strong antiferromagnetic interaction between Cr and Ge atoms. The magnetic interaction between Ge and Ge atoms are almost antiferromagnetic behaviors. The magnetic exchange interaction are occurred over the sevaral Ge atom layers. The magnitude of this interaction depends number of Ge atom.

• Journal of Korea Foundry Society
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• v.37 no.2
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• pp.31-37
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• 2017

A new form of austenitic heat-resistant ductile iron was developed and its microstructures and elevated temperature properties were compared to those of Ductile Ni-Resist D5S. According to JMatPro calculations, it was predicted that Mo-rich carbides would be crystallized before the eutectic reaction starts in the developed alloy. At the austenite cell boundaries of the developed alloy, both Mo-rich carbides and Cr-rich carbides were found. In addition, Ni-silicides were found adjacent to Cr-rich carbides in D5S specimen and were identified as $Ni_2Si$. The developed alloy also had greater yield strength and lower tensile strength levels with less elongation due to the dissolution of Mo atoms into the austenite matrix and the precipitation of Mo-rich carbides. From the results of elevated temperature tensile tests and stress-rupture tests, it was found that the developed alloy had elevated temperature properties superior to those of D5S. This was due to the pinning effect of the dissolved Mo atoms in the austenite matrix.

• Journal of the Korean Magnetics Society
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• v.16 no.2
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• pp.115-120
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• 2006

Electronic and magnetic structure of $Cr_2Te_3$ have been studied, which is a material with complex magnetic structure. Density of states and magnetic moments show better agreement with experiments than LDA if they are obtained with the correlation effect of Cr-d electrons taken into account by the LDA+U method. In these calculations, the magnitude of the correlation effect is found to be 1.7 eV. It is shown that the magnitude of experimental magnetic moments of Cr atoms can be explained if the ferromagnetic states and the ferrimagnetic states have the same energy to be degenerate.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.761-763
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• 1998

In this paper, Co-Cr thin films which are known for a excellent perpendicular magnetic recording media were prepared. Changing target- substrate distance, Ar gas pressure and arriving atoms, the incident angle and c-axis orientation properties by using the facing targets sputtering system. We evaluated the c-axis dispersion angle by measu ring half-height width with Micro area X-Ray Diffractometer, measured the thickness of thin film with Ellipsometer. The magnetic properties were compared measuring in-plane squareness and perpendicular coercivity with vibrating sample Magnetometer.