http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Y. R. Uhm,S. H. Lim 한국자기학회 2001 Journal of Magnetics Vol.6 No.4
The switching characteristics and the magnetization-flop behavior in magnetic tunnel junctions exchange biased by synthetic antiferromagnets (SyAFs) are investigated by using a computer simulations based on a single-domain multilayer model. The bias field acting on the free layer is found to be sensitive to the thickness of neighboring layers, and the thickness dependence of the bias field is greater at smaller cell dimensions due to larger magnetostatic interactions. The resistance to magnetization flop increases with decreasing cell size due to increased shape anisotropy. When the cell dimensions are small and the synthetic antiferromagnet is weakly, or not pinned, the magnetization directions of the two layers sandwiching the insulating layer are aligned antiparallel due to a strong magnetostatic interaction, resulting in an abnormal magneto resistance (MR) change from the high-MR state to zero, irrespective of the direction of the free-layer switching. The threshold field for magnetization-flop is found to increase linearly with increasing antiferromagnetic exchange coupling in the synthetic antiferromagnet. Irrespective of the magnetic parameters and cell sizes, magnetization flop does not exist near zero applied field, indicating that magnetization flop is driven by the Zeeman energy.
Uhm, Y.R.,Lee, M.K.,Rhee, C.K. The Korean Magnetics Society 2007 韓國磁氣學會誌 Vol.17 No.2
The Cu oxide nano powders were synthesized by levitational gas condensation (LGC) method and their high heterogeneous catalytic effects of oxidation of 2,3,5-trimethyl-1,4-hydroquinone (TMHQ) and catalase activity were studied. The nano powders consist of mainly $Cu_2O$. The catalytic effect which was clarified by the oxidation of TMHQ and the activity of catalase, was found to depend on the amount of $Cu_2O$ phase and the particle size.
Synthesis of Metal and Ceramic Magnetic Nanoparticles by Levitational Gas Condensation (LGC)
Y. R. Uhm,H. M. Lee,G. J. Lee,C. K. Rhee 한국자기학회 2009 Journal of Magnetics Vol.14 No.2
Nickel (Ni) and ferrite (Fe₃O₄, NiFe₂O₄) nanoparticles were synthesized by LGC using both wire feeding (WF) and micron powder feeding (MPF) systems. Phase evolution and magnetic properties were then investigated. The Ni nanopowder included magnetic-ordered phases. The LGC synthesis yielded spherical particles with large coercivity while the abnormal initial magnetization curve for Ni indicated a non-collinear magnetic structure between the core and surface layer of the particles. Since the XRD pattern cannot actually distinguish between magnetite (Fe₃O₄) and maghemite (γ-Fe₂O₃) as they have a spinel type structure, the phase of the iron oxide in the samples was unveiled by Mossbauer spectroscopy. The synthesized Ni-ferrite consisted of single domain particles, including an unusual ionic state. The synthesized nanopowder bore an active surface due to the defects that affected abnormal magnetic properties.