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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Magnetics
Journal Basic Information
Journal DOI :
The Korean Magnetics Society
Editor in Chief :
Volume & Issues
Volume 6, Issue 4 - Dec 2001
Volume 6, Issue 3 - Sep 2001
Volume 6, Issue 2 - Jun 2001
Volume 6, Issue 1 - Mar 2001
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Sol-Gel Synthesis and Transport Properties of
Granular Thin Films
Shim, In-Bo ; Kim, Sung-Baek ; Ahn, Geun-Young ; Yun, Sung-Roe ; Cho, Young-Suk ; Kim, Chul-Sung ;
Journal of Magnetics, volume 6, issue 1, 2001, Pages 1~4
We have used acetic acids ethanol and distilled water as a solvent to synthesize
(LSMFO) precursor. Crack-free LSMFO granular polycrystalline thin films have been deposited on thermally oxidized silicon substrates by spin coaling. The dependence of crystallization, surface morphology, magnetic and transport properties on annealing temperature was investigated. With increasing annealing temperature, the metal-semiconductor (insulator) transition temperature and the magnetic moment decrease while the resistivity increases. The lattice constants remain almost unchanged. For LSMFO thin films, spin-dependent interfacial tunneling and/or scattering magnetoresistance were observed. Our results indicate that the annealing temperature is very important in determining the intrinsic and extrinsic magnetotransport properties.
Magnetic Characteristics of Ancient Plain Coarse Pottery and Pantiles from Cheju Island
Yoon, Tae Gun ; Ko, Jeong Dae ; Hong, Sung Rak ;
Journal of Magnetics, volume 6, issue 1, 2001, Pages 5~8
Cheju island is composed of volcanic tuff. The soil in Cheju island has principally sprung from basalt and partially made up of trachyte, and andesite. Also ancient relics, plain coarse pottery kilns and pantiles kilns are homogeneously distributed all over the Cheju island. In this study samples of plain coarse pottery and pantiles from five regions of Cheju island have been examined through X-ray fluorescence spectrometer and Mossbauer spectroscopy. It is thought that these samples be partially formed from neutral volcanic rock like trachyte and the valence state of iron is almost
. Also the magnetic hyperfine field of goethite contained in these samples is less than synthetic goethite. This result shows the degradation of magnetic order caused by the partial substitution of diamagnetic positive ion
in the goethite lattice.
Magnetic Properties and Magnetoimpedance Effect in Mumetal Thin Films
Cho, Wan-Shik ; Yoon, Tae-Sick ; Lee, Heebok ; Kim, Chong-Oh ;
Journal of Magnetics, volume 6, issue 1, 2001, Pages 9~12
The dependence of the magnetoimpedance effect (MI) on magnetic properties has been investigated in mumetal thin films prepared by rf magnetron sputtering. Coercivity of thin films prepared at 400 W was about 0.4 Oe, and the magnetic anisotropy field of films deposited under a uniaxial magnetic field decreased with increasing film thickness. The saturation magnetization of mumetal films increased with rising input power and thickness and was smaller than that of permalloy films. Transverse incremental Permeability (TPR) of films of 1
thick increased with increasing effective permeability. The magneto impedance ratio (MIR) was proportional to TPR in films 1
thick but in spite of lower effective permeability at higher thicknesses, MIR increased due to skin effect. The height of the double peaks in the MIR curves decreased with decreasing anisotropy and thickness. The maximum MIR value for a 4
thick 75% at 36.5 MHz.
Manufacture of Permalloy Soft Magnets by Powder Injection Molding
W.Y. Jeung ; Park, J.W. ;
Journal of Magnetics, volume 6, issue 1, 2001, Pages 13~18
Permalloy soft magnets have been produced by the powder injection molding process. Rheological characteristics of mixtures, debinding conditions, and the magnetic properties of permalloy after sintering have been investigated. A permalloy soft magnet with a permeability of 14200 could be obtained by preparing a mixture with a powder loading of 65.4 vol % and a PP/PEG binder systems solvent extraction, thermal debinding, and subsequent sintering at 1350
in hydrogen. The permalloy soft magnet sintered in hydrogen had 95% of theoretical density and a magnetic induction of 13.2 kG in an applied magnetic field of 50 Oe.
Effects of Magnetic Layer Thickness on Magnetic Properties of CoCrPt/Ti/CoZr Perpendicular Media
Hwang, M.S. ;
Journal of Magnetics, volume 6, issue 1, 2001, Pages 19~22
Change of magnetic properties in CoCrPt/Ti perpendicular media with varying CoCrPt film thickness has been studied. As the CoCrPt film thickness increases from 25 nm, the Ms (saturation magnetization) increases rapidly at first and then more gradually. This Ms behavior is associated primarily with the formation of an "amorphous-like"reacted layer created by intermixing of CoCrPt and Ti at the CoCrPt/Ti interface and secondarily with a change of the Cr segregation mode with varying CoCrPt film thickness. Magnetic domain structure distinctively changes with increasing CsCrPt magnetic layer (ML) thickness. Also the strength of exchange coupling measured from the slope in the demagnetizing region of the M-H loop changes with ML thickness. The expansion of lattice parameters a and c at smaller film thickness suggests that the Cr segregation mode may be connected with the residual stress of the films. Finally, the negative nucleation field (Hn) shows a unique behavior with the change of strength of the exchange interaction.teraction.
Barium Hexaferrite Thin Films Prepared by the Sol-Gel Method
An, Sung-Yong ; Lee, Sang-Won ; Shim, In-Bo ; Yun, Sung-Roe ; Kim, Chul-Sung ;
Journal of Magnetics, volume 6, issue 1, 2001, Pages 23~26
(BaM) thin films have been prepared by the sol-gel method. A solution of Ba-nitrate and Fe-nitrates was dissolved in solvent with the stoichiometric ratio Ba/Fe=1/10. Films were spin-coated onto
Si substrates, dried and then heated in air at various temperatures. In films prepared at a drying temperature
and a crystallizing temperature 650
, single-phase BaM was obtained. High coercivities were obtained in these nano-crystalline thin films, 4~5.5 kOe for hexaferrite. Polycrystalline BaM/
/Si(100) thin films were characterized by Rutherford backscattering (RBS), thermogravimetry (TGA), differential thermal analysis (DTA), x-ray diffraction (XRD), and vibrating sample magnetometry (VSM), as well as Fourier transform infrared spectroscopy (FTIR). The perpendicular coercivity
and in-plane coercivity
after annealing at 650
for 2 hours were 4766 Oe and 4480 Oe, respectively, at room temperature, under a maximum applied field of 10 kOe.
Nondestructive Evaluation of Residual Life of 1Cr-1Mo-0.25V Steel from Reversible Magnetic Permeability
K.S. Ryu ; S.H. Nahm ; Kim, Y.I. ; K.M. Yu ; Kim, Y.B. ; Cho, Y. ; D. Son ;
Journal of Magnetics, volume 6, issue 1, 2001, Pages 27~30
We present a new procedure to evaluate the residual life of 1Cr-1Mo-0.25V steel from reversible magnetic permeability. The method is based on the existence of first harmonics in the differential magnetization around the coercive force. The apparatus is based on the detection of the voltage induced in a coil using a lock-in amplifier tuned to the frequency of the exciting coil. Results obtained for the first harmonics and Vickers hardness on aged samples show that the peak interval of reversible permeability and Vickers hardness decrease as aging time increases. The correlation between Vickers hardness and the peak interval of the reversible permeability may be used to evaluate the residual life of 1Cr-lMo-0.25V steel, nondestructively.
Optimum Design of a Non-Destructive Testing System to Maximize Magnetic Flux Leakage
Park, G.S ; Jang, P.W ; Rho, Y.W ;
Journal of Magnetics, volume 6, issue 1, 2001, Pages 31~35
This paper describes the design method of a magnetic system to maximize the magnetic flux leakage (MFL) in a non-destructive testing (NDT) system. The defect signals in a MFL type NDT system mainly depend on the change of the magnetic leakage flux in the region of a defect. The characteristics of the B-H curves are analysed and a design method to define the operating point on B-H curves for maximum leakage is performed. The computed MFL signal by a nonlinear finite element method is verified by measurement using Hall sensors mounted on the 6 legs PIG, the traveling detector unit in gas pipe, in an 8 inch test tube with defects. The rhombic defects could be successfully identified from the defect signals.
Sensitivity of an Anisotropic Magnetoresistance Device with Different Bias Conditions
Kim, T.S. ; Kim, K.C. ; Kim, Kibo ; K. Koh ; Y.J. Song ; Song, Y.S. ; Suh, S.J. ; Kim, Y.S. ;
Journal of Magnetics, volume 6, issue 1, 2001, Pages 36~41
A micromagnetic model and a single-domain model simulation programs were used to analyze the sensitivity of a
permalloy strip as a magnetoresistance sensor with bias fields of various directions and magnitudes. The micromagnetic model agrees with the measured sensitivity data better than the single-domain model. The data show the highest peak sensitivity with the bias field at 90
to the current. The peak sensitivity decreases and the peak broadens as the bias angle decreases. The simulation using the micromagnetic model shows that a bias angle smaller than 90
eads to magnetization patterns which are free from closure domains or vertices over a wider range of bias fields.