• Journal of the Korean Magnetics Society
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• v.3 no.3
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• pp.208-214
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• 1993

In order to investigate the origin of an increase in the coercivity with the Ta addition to Co-Cr films, the perpendicular magnetic anisotropy of Co-Cr film and CoCrTa film was measured by a torque magnetometer and VSM. In Co-Cr binary alloy film, the uniaxial anisotropy increased with increasing Cr content. The perpendicular magnetic anisotropy of $Co_{81.7}Cr_{16.7}Ta_{1.6}$ film was larger than that of $Co_{81}Cr_{19}$ film, both of which were deposited at the same substrate temperature of $100^{\circ}C$. The change in the perpendicular magnetic anisotropy with annealing was studied to understand the Ta addition effect. The amount of decrease in perpendicular magnetic anisotropy of the CoCrTa film by the annealing was larger than that of Co-Cr film. And the perpendicular magnetic anisotripies of Co-Cr film and CoCrTa film after annealing were almost the same. The cause of this was interpretated as the enhanced segregation of solute atoms in the Ta added thin film in the as-deposited state. The enhanced segregation of solute atoms increases the perpendicular magnetic anisotropy of the film, and causes the increase of perpendicular coercivity of the film.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.3
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• pp.281-286
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• 2002

In odder to investigate the magnetic properties of CoCr-based bilayered thin films on kind of underlayer, we introduced amorphous Si layer to Co-Cr(-Ta) magnetic layer as underlayer. First, we prepared CoCr and CoCrTa single layer using the Facing Targets Sputtering system to investigate theirs properties. It was revealed that with increasing the film thickness of CoCr, CoCrTa single layer, crystalline orientation and perpendicular coercivity was improved. The CoCrTa thin film showed bettor crystalline and magnetic characteristics than CoCr thin film. As a result of investigating magnetic properties of CoCr and CoCrTa magnetic layer on introducing the Si underlayer, perpendicular coercivity and saturation magnetization of CoCr/Si and CoCrTa/Si bilayered thin film were decreased due to the increased grain size and diffusion of Si atoms to magnetic layer. And they showed constant with increasing the film thickness of Si thin film. However, in case of CoCrTa/Si bilayered thin film, in-plane coercivity was controlled low at about 250Oe. The c-axis orientations of CoCr/si and CoCrTa/Si bilayered thin film showed a good crystalline characteristics as about $2^{\circ}$.

• Journal of the Korean Magnetics Society
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• v.9 no.5
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• pp.256-262
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• 1999

Sputter deposited CoCr(Mo)/Si film were studied with emphasis on the correlation between magnetic properties and crystallographic orientation. The perpendicular coercivities of CoCr films decreased with Si underlayer thickness, whereas those of CoCrMo films increased with Si underlayer thickness. It has been explained that additions of the larger atomic radius Mo atoms in CoCr films impedes crystal growth resulting in a decrease in grain size, thus this small grain size may induce high perpendicular coercivity. The c-axis alignment of CoCrMo film was improved due to addition of 2at.%Mo. It means CoCrMo layer grow self-epitaxial directly from orientation and structure of Si underlayer when the main layer grow on underlayer.

• Applied Science and Convergence Technology
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• v.26 no.1
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• pp.16-19
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• 2017

A thin metal layer of molybdenum is placed between the conventional barrier layer and the stainless steel substrate for investigating the diffusion property of iron (Fe) atoms. In this study, the protection probability was confirmed by measuring the concentration of out-diffused Fe using a SIMS depth profile. The Fe concentration of chromium (Cr) barrier layer with 10 nm molybdenum (Mo) layer is 5 times lower than that of Cr barrier without the thin Mo layer. The insertion of a thin Mo metal layer between the barrier layer and the stainless steel substrate effectively protects the out-diffusion of Fe atoms.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.23-27
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• 1997

The luminescence and excitation spectra of [Cr(trans-diammac)](ClO4)3 (trans-diammac=trans-6, 3-dimethyl-l, 4, 8, 11-tetraazacyclotetradecane-6, 13-diamine) taken at 77 K are reported. The mid and far-infrared spectra at room-temperature are also measured between 4000 cm-1and 50 cm-1. In the excitation spectrum the 2Eg components are splitted by 102 cm-1. Using the observed electronic transitions, a ligand field analysis was performed to determine more detailed bonding properties of the coordinated atoms toward chromium(Ⅲ). According to the results, we can confirm that the six nitrogen atoms have a strong σ-donor character, and the trans-diammac secondary amine has a greater value of eσ than does the primary amine.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.963-968
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• 2008

For the [$Cr_2(H_2tmp)_2Cl_4$] compound, simplified models with two bridging methoxo ligands have been studied. The influence of the bridging Cr-O-Cr bond angles on the exchange coupling between metal atoms in the model compound has been analyzed by means of density functional calculations with the broken-symmetry approach. Coupling constant calculated for the full structure is in good agreement with the experimentally reported value, confirming the validity of the computational strategy used in this work to predict the exchange coupling in a family of related dinuclear Cr(III) compounds. The calculations indicate a good correlation between the calculated coupling constant and the sum of the squared energy gap of three pairs of metal $t_{2g}$ OMSOs with a limited variation of the Cr-O-Cr angle. The spin density distribution and the mechanism of magnetic coupling interactions are discussed.

• Elastomers and Composites
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• v.54 no.1
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• pp.40-53
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• 2019

The physical properties of chloroprene rubber (CR) compounds reinforced with networked silicas were investigated by comparing them to those reinforced with conventional silica to observe the effect of the organic connection bonds combining silica particles on their cure, tensile, and aging performance. The introduction of networked silica to CR increase in silica content to 80 phr in rubber, while the content of conventional silica was limited to 60 phr. The CR compounds reinforced with networked silica showed higher resistance to combustion. The gradual increases in delta torque, Mooney viscosity, and modulus of silica-filled CR compounds with silica content were mainly attributed to the specific interaction between the chlorine atoms of CR and the hydroxyl groups of silica. The CR compounds reinforced with networked silica showed low compression set and heat build-up and maintained their high modulus even after thermal, oil, and ozone aging.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.977-982
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• 2004

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 {$L_a$ = benzoate(bz) or chlorobenzoate(cbz)} leads to a new compound $[Cr([14]-decane)(bz)_2]ClO_4$ or $[Cr([14]-decane)(cbz)_2]ClO_4$. These complexes have been characterized by a combination of elemental analysis, conductivity, IR and Vis spectroscopy, mass spectrometry, and X-ray crystallography. The crystal structure of $[Cr([14]-decane)(cbz)_2]^+$ was determined. The complex shows a distorted octahedral coordination environment with the macrocycle adopting a folded cis-V conformation. The angle $N_{axial}-Cr-N_{axial}$ deviates by $14.5^{\circ}$ from the ideal value of $180^{\circ}$for a perfect octahedron. The bond angle cis-O-Cr-O between the Cr(III) ion and the two carboxylate oxygen atoms of the monodentate p-chlorobenzoate ligands is close to 90$^{\circ}$. The FAB mass spectra of the $cis-[Cr([14]-decane)(La)_2]ClO_4$ display peaks due to the molecular ions $[Cr([14]-decane)(bz)_2-H]^\;,\;[Cr([14]-decane)(cbz)_2-2H]^$ at m/z 578, 646, respectively.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.184-188
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• 2002

Unsaturated $Cr(CO)_x(1{\leq}x{\leq}5)$molecules were generated in the gas phase from photolysis of $Cr(CO)_6$vapor in He using an unfocussed weak UV laser pulse and their reactions with $O_2$ and $N_2O$ have been studied. The formation and disappearance of the ground state CrO molecules were identified by monitoring laser-induced fluorescence(LIF) intensities vs delay time between the photolysis and probe pulses. The photolysis laser power dependence as well as the delay time dependence of LIF intensities from the CrO orange system showed different behavior as those from ground state Cr atoms, suggesting that the ground state CrO molecules were generated from the reaction between $O_2/N_2O$ and photo-fragments of $Cr(CO)_6$ by one photon absorption. The depletion rate constants for the ground state CrO by $O_2$ and $N_2O$ are $5.4{\pm}0.2{\times}10^{-11}$ and $6.5{\pm}0.4{\times}10^{-12}cm^3molecule^{-1}s^{-1}$, respectively.

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.721-725
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• 2013

Reaction between 2-pyridinecarboxylic acid (Hpic) and $K_3[Cr(O_2)_4]$ give complex $[Cr(pic)_3].H_2O$ (1) which is characterized by elemental analysis and spectroscopic methods (FT-IR, Raman) and X-ray crystallography. In the crystal structure of 1, chromium atom with coordinated by three nitrogen and three oxygen atoms has a distorted octahedral geometry. Also a water molecule is incorporated in crystal network. Each water molecule acts as hydrogen bond bridging and connects two adjacent complexes by two $O-H{\cdots}O$ hydrogen bonds.