Seon-Keun Choi

Abstract Ba‐hexaferrite and Ni 0.5 Zn 0.5 ferrite nano composites have been successfully fabricated by a self‐propagating combustion method. Transmission electron microscopy and X‐ray diffractometer analysis showed that two ferrite phases were homogeneously distributed and the measured grain size of them around 20nm. The saturation magnetizations of the composites were revealed to be increased compared with the theoretical values. These increments of the saturation magnetization values could be

Ferromagnetic nanoparticles with a core/shell structure were fabricated by a self-propagating combustion method and subsequent hydrogen reduction process. Before the reduction process, synthesized particles were Fe oxide phases. Transmission electron micrographs confirmed that the nanoparticles were composed of α-Fe core and Fe–Al oxide shell after the reduction process. The saturation magnetization of the nanoparticles was measured about 180 emu/g and the permeability kept constant value of abo

Abstract A broadband coplanar waveguide method, recognized as a simple and effective broadband permeability measurement tool, was used to measure the frequency dependent permeability of various magnetic thin films. It was revealed that measured permeability was strongly dependent on the dimension of the films and the geometry of the waveguide. This dependency was proven to result from the confinement of magnetic fields in the films by LLG equation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, W

We investigated charged dust and its effect on RF plasma by using a planar electric probe in a large-scale device. In background plasmas, the particle density is 108 to 109 cm−3 and the electron temperature is 2 to 4 eV. When dust is contained in plasma, it is negatively charged by electrons attached to the dust. The charged dust density and the charge were calculated by comparing dusty helium plasma to pure helium plasma. Depending on the increase in the amount of dust, the charged dust density