• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.145-145
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• 2003

• Journal of the Korean Magnetics Society
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• v.1 no.2
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• pp.15-21
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• 1991

The magnetic properties of the $Y_{1}Ba_{2}Cu_{3-x}Sn_{x}O_{7-y}$ superconductor were studied as a function of Sn concentration by utilizing both the vibrating sample magnetometer (VSM) and torque magnetometer. Unlike the cases where Fe and Co were substituted for Cu, the superconducting transition temperature was maintained above 90 K until x reached the value of 0.36. The lower critical field $H_{c1}(T)$ and upper critical field $H_{c2}(T)$ are measured as a function of temperature and external magnetic field, respectively. By aid of these results, $H_{c1}(0)$.($H_{c2}(0)$), the coherence length ${\varepsilon}_{0}$, the penetration depth ${\lambda}_{0}$, and the Ginzburg-Landau parameter k were oqtained. Flux pinning was also observed in the sample.

• Journal of the Korean Magnetics Society
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• v.17 no.1
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• pp.43-46
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• 2007

The samples were synthesized by using a solid state reaction. The X-ray diffraction pattern for $Ti_{0.96}Co_{0.02}Fe_{0.02}O_2$ showed a pure rutile phase with tetragonal structures. Mixtures of the proper proportions of the elements sealed in evacuated quartz ampoule were heated at $870{\sim}930^{\circ}C$ for one day and then slowly cooled down to room temperature at a rate of $10^{\circ}C/h$. In order to obtain single phase material, it was necessary to grind the sample after the first firing and to press the powders into pellets before annealing them for a second time in evacuated and sealed quartz ampoule. Magnetic properties have been investigated using the vibrating sample magnetometer(VSM). Room temperature magnetic hysteresis(M-H) curve showed an obvious ferromagnetic behavior and the magnetic moment per Fe atom under the applied of 0.8T was estimated to be about $1.3{\mu}_B/CoFe$. But the magnetic moment per Fe atom under the applied of 0.8T was estimated to be about $0.02{\mu}_B/CoFe$ without Ti-getter.

• Journal of the Korean Magnetics Society
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• v.8 no.1
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• pp.6-12
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• 1998

Fe-N(iron-nitrogen) crystal phases were prepared by nitrogen ion implantation into $\alpha$-Fe foil with Plasma Source Ion Implantation (PSII). Ion implantation time of sample is treated 15 minutes(FeN15) and 30 minutes (FeN30). The nitrogen depth profiles measured by Auger electron spectroscopy (AES) were determined to be about 12000 $\AA$ and 4000 $\AA$ for the samples of FeN15 and FeN30, respectively. The results of vibrating sample magnetometer (VSM) show that the saturation magnetization of the samples of as-implanted FeN15 and FeN30 was higher than that of pure $\alpha$-Fe foil, which may be owing to $\alpha$'-$Fe_8N$ or $\alpha$"-$Fe_{16}N_2$ phases. Accordingly this study shows the possibility of the partial formation of $\alpha$' or $\alpha$" phase in iron nitrogen produced by PSII method.II method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.30-33
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• 2001

This thesis deal with ferroelectric and ferrimagnetic materials, PZT/Ferrite ceramics. We conducted test of magnetical and electrical measurement. From this measurement, We obtained tunability and we can control characteristic impedance($Z_0$) from permeability($\mu$) and dielectric constant($\varepsilon$) for impedance matching in transmission line.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.30-33
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• 2001

This thesis deal with ferroelectric and ferrimagnetic materials, PZT/Ferrite ceramics. We conducted test of magnetical and electrical measurement. From this measurement, We obtained tunability and we can control characteristic impedance(Z$_{0}$) from permeability($\mu$) and dielectric constant($\varepsilon$) for impedance matching in transmission line.e.

• Journal of Magnetics
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• v.2 no.3
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• pp.72-75
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• 1997

The temperature dependent saturation magnetization curve of amorphous Fe67 Co18B14Si1, alloy was measured using a SQUID magnetometer and vibrating sample magnetometer from 5 K up to 800 K. Inelastic neutron neutron scattering measurements also have been used to study the long wavelength spin dynamics of this high Tc amorphous ferromagnetic alloy. The magnon dispersion curve exhibit the conventional quadratic relationship E = D (T) q2 + $\Delta$, typical of an iso=obtained from a low temperature magnetization curve, which was consistent with the value obtained from the analysis oif inelastic neutron scattering data after consideration of its temperature dependence.

• Journal of the Korean Ceramic Society
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• v.40 no.1
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• pp.62-68
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• 2003

Ba-ferrite particles added with Co and Ti, which were known well the additives for the control in coercivity, were synthesized by sol-gel method. In the range 90 to 120 minute reaction time, a stable sol solution which showed no change with temperature, pH, viscosity and aging time. After dried and heat treatment of sol solution, Ba-ferrite phase formed at $700^{\circ}C$ with Differential Thermal Analysis(DTA) and X-Ray Diffractometer(XRD) measurement. The crystallinity became to be better with increasing the temperature. It were showed by Scanning Electron Microscopy(SEM) that Ba-ferrite increased to particle sizes as increasing heating temperature and obtained of narrow particles size distribution. Also, magnetic characteristics of Ba-ferrite powders Co and Ti added were observed by a Vibrating Sample Magnetometer(VSM). Saturation magnetization$(M_s)$ was not much changed, however. the coercivity$(H_c)$dramatically dropped with addition of Co and Ti.

• Journal of the Korean Magnetics Society
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• v.19 no.6
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• pp.216-221
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• 2009

Y-type barium ferrite $Ba_2Co_2Fe_{12}O_{22}$ was synthesized by a solid state reaction method. Effects of metal ion mole ratio and calcination temperatures on magnetic properties and microstructures of the synthesized powders were investigated. Phase analysis and microstructure observation were performed with a XRD (X-ray diffractometer) and a FESEM (field effect scanning electron microscope), respectively. Magnetic properties of the powders were measured with a VSM (vibrating sample magnetometer). Single phase Y-type was synthesized when metal ion mole fraction $Fe^{3+}:\;Ba^{2+}:\;Co^{2+}$ was 6 : 1 : 1 and calcination temperature was $1050\;{^{\circ}C}$. High saturation magnetization value of 39.1 emu/g was obtained when metal ion mole fraction $Fe^{3+}:\;Ba^{2+}:\;Co^{2+}$ was 8 : 1 : 1 and calcination temperature was $1200\;{^{\circ}C}$.

• Journal of the Korean Magnetics Society
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• v.8 no.4
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• pp.203-209
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• 1998

Crystallographic and magnetic properties of single phase garnet $Y_{3-x}Bi_xFe_5O_{12}$ (x=0.0, 0.25, 0.5, 0.75, 1.0) were studied by using x-ray diffraction, Mossbauer spectroscopy and vibrating sample magnetometer (VSM). Ultra-fine polycrystalline cubic samples have been prepared by sol-gel method. The lattice constant increase linearly with increasing an amount of Bi. Annealing temperature was larger than 800 $^{\circ}C$ for the growth of a single-phase garnet powder. The second phase of garnet, $(BiFeO_3)$, was at 1000 $^{\circ}C$ for x=0.75, and 950 $^{\circ}C$ for x=1.00. From Mossbauer spectroscopy and VSM measurements, the magnetization and the coercivity were decreased and the Curie temperature $Y_{3-x}Bi_xFe_5O_{12}$(x=0.0, 0.25, 0.5, 0.75, 1.0) was slightly increased as increasing the Bi content.