1. 교환 결합력을 갖는 CoFe/MnIr(2.5 nm) 박막의 회전 이방성 자기장 특성

    Seok Soo Yoon and Dong Young Kim

    Journal of the Korean Magneitcs Society, 30 Jun 2017, Vol.27 , No.3, pp.77-81

    Number of citation : 0

    교환 결합력을 갖는 CoFe/MnIr(2.5 nm) 박막의 회전 이방성 자기장 특성

    The rotatable anisotropy effect was observed in the ferromagnetic resonance measurement in exchange coupled ferromagnetic/antiferromagnetic thin films and it was due to rotation of antiferromagnetic layer by the exchange coupling energy. We analyzed the CoFe thickness dependence of rotatable anisotropy field and ferromagnetic resonance linewidth in exchange coupled CoFe(tF)/MnIr(2.5 nm) thin films. The rotatable anisotropy field was inversely propositional to the CoFe thickness and it was well fitted by the rotatable anisotropy energy of 0.96 erg/cm2. The ferromagnetic resonance linewidth were linearly propositional to the rotatable anisotropy field in tF < 50 nm, while it was more dominated by the eddy current effect in tF > 50 nm.

  2. Nb 버퍼층과 거대자기저항-스핀밸브 하이브리드 다층박막의 자기저항 특성

    Woo-Il Yang , Jong-Gu Choi and Sang-Suk Lee

    Journal of the Korean Magneitcs Society, 30 Jun 2017, Vol.27 , No.3, pp.82-86

    Number of citation : 1

    Nb 버퍼층과 거대자기저항-스핀밸브 하이브리드 다층박막의 자기저항 특성

    The IrMn based GMR-SV films with three different buffer layers were prepared on Corning glass by using ion beam deposition and DC magnetron sputtering method. The major and minor magnetoresistance curves for three different buffer layers beneath the structure of NiFe(15 nm)/CoFe(5 nm)/Cu(2.5 nm)/CoFe(5 nm)/NiFe(7 nm)/IrMn(10 nm)/Ta(5 nm) at room temperature have shown different magnetoresistance properties. When the samples were annealed at 250 ℃ in vacuum, the magnetoresistance ratio, the coercivity of pinned ferromagnetic layer, and the interlayer coupling field of free ferromagnetic layer were enhanced while the exchange bias coupling field did not show noticeable changes.

  3. Magnetic Properties and Application of Caltalysts in Biginelli Reaction for the Ni and Ni@C Synthesized by Levitational Gas Condensation (LGC)

    Young Rang Uhm

    Journal of the Korean Magneitcs Society, 30 Jun 2017, Vol.27 , No.3, pp.87-91

    Number of citation : 1

    Magnetic Properties and Application of Caltalysts in Biginelli Reaction for the Ni and Ni@C Synthesized by Levitational Gas Condensation (LGC)

    Carbon-encapsulated Ni and metal Ni nanoparticles were synthesized by levitational gas condensation (LGC). Methane (CH4) gas was used to coat the surface of the Ni nanoparticles. The Ni particles had a core diameter of 10 nm, and were covered by 2~3 nm thin carbon layers with multi-shells structure.The low magnetization comparing with the Ni nanoparticles without carbon-shell results in the coexistence of nonmagnetic carbon and a large surface spin percentage with disordered magnetization orientation for the nanoparticles. Biginelli reactions in the presence of L-proline and Ni and carbon encapsulated Ni nanoparticles were carried out to change the ratio between stereoisomers. The obtained S-enantiomers for 3,4-dihydropyrimidine (DHPM) using catalysts of Ni, and Ni@C was an excess of about Δ~7.4% and Δ~19.6 %, respectively. The nanopowders were fully recovered using magnet to reuse as a catalyst. The Ni@C was shown at same yield to formation of 3,4-DHPM, though it was recycled for catalyst in the reaction.

  4. 강한 펄스자기장 자극에 의한 적혈구 연전현상의 활동성 조사

    Do Guwn Hwang

    Journal of the Korean Magneitcs Society, 30 Jun 2017, Vol.27 , No.3, pp.92-97

    Number of citation : 0

    강한 펄스자기장 자극에 의한 적혈구 연전현상의 활동성 조사

    It is widely known that pulsed magnetic field (PMF) is very useful tool to manipulate chemical and physiological processes in human body. The purpose of our study is to observe dynamics of rouleaux patterns of red blood cells (RBC) under PMF. The aggregation of RBCs or rouleaux formation is caused by fibrinogen in blood plasma. The maximum magnetic field intensity is 0.27 T and pulse time of 0.102 msec and pulse repetition rate was 1 Hz. PMF stimulus was applied to the palm of left hand for 5, 10, 15 and 20 min. Live blood analysis was used in vitro in order to quantitatively estimate the velocity of RBC exposed to PMF stimulus. The velocity of stacked-RBC of 10 minute PMF stimulus was increased up to 8 × 10−4m/sec, but it decreased rapidly as the time passed. The results of present study have adduced that PMF stimulus on hand provide the improvement of RBC rouleaux formation, increase of RBC’s moving velocity as well as low blood viscosity.

  5. 소해함을 위한 실시간 폐회로 소자 기법

    Byungsu Kang , Dong-Hun Kim , Chang-Seob Yang , Hyun-Ju Chung and Dong-Wook Kim

    Journal of the Korean Magneitcs Society, 30 Jun 2017, Vol.27 , No.3, pp.98-103

    Number of citation : 0

    소해함을 위한 실시간 폐회로 소자 기법

    In this paper, an efficient closed-loop degaussing technique is proposed to control real-time degaussing currents required for a minesweeper. To achieve this, new principle and algorithm for controling degaussing currents are presented, and they are compared to conventional ones. To validate the proposed method, a minesweeper mockup is tested by means of a rigorous numerical simulation. Results show that the method successfully yields satisfactory degaussing performances for several course angle changes of the mockup.

  6. 4차 산업혁명과 자기학(1) - 4차 산업혁명의 개황 -

    Hi-Jung Kim

    Journal of the Korean Magneitcs Society, 30 Jun 2017, Vol.27 , No.3, pp.104-113

    Number of citation : 0

    4차 산업혁명과 자기학(1) - 4차 산업혁명의 개황 -

    K. Suwab, a chairman of the World Economic Forum (WEF), reported the emerging of the 4th industrial revolution by the convergence of artificial intelligence and robot as well as the fusion of true and virtual reality in the WEF 2016. He suggested the 4th industrial revolution would change greatly the paradigm of industry and society in the future, and damage the security and quality of the human job severely. In this review the argument of terminology, the impacts on economics, industry technologies and jobs by the 4th industrial revolution have been discussed. And the role of magnetics on the 2-4th industrial revolutions was reviewed briefly.