• Proceedings of the Materials Research Society of Korea Conference
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• 1993.11a
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• pp.44-44
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• 1993

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.33-33
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• 1994

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.17-17
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• 1996

• Korean Journal of Materials Research
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• v.10 no.11
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• pp.755-759
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• 2000

The influence of $O_2$partial presure on saturation magnetization, coercivity and effective permeability(0.5~100MHz) of as-deposited Fe-Sm-O thin films, which were fabricated by RF magnetron reactive sputtering method, were investigated. The nanocrystalline Fe(sub)83.4Sm(sub)3.4O(sub)13.2 thin film fabricated at $O_2$partial pressure of 5% exhibits the best magnetic softness with saturation magnetization of 18kG, coercivity of 0.82 Oe and effective permeability about 2,600 at 0.5~100MHz. $\alpha$-Fe grain size is decreased with increasing $O_2$partial pressure. In case of $O_2$partial pressure of 10%, it is observed that FeO compound is formed and soft magnetic properties are decreased. The electrical resistivity of Fe-Sm-O thin films were increased with increasing $O_2$partial pressure, the electrical resistivity of Fe(sub)83.4Sm(sub)3.4O(sub)13.2 thin film with the best soft magnetic properties was 130 $\mu$$\Omega$cm. Therefore, It is assumed that the good soft magnetic properties of Fe(sub)83.4Sm(sub)3.4O(sub)13.2 thin film results from high electrical resistivity and decreasing $\alpha$-Fe grain size due to precipitation of Sm-Oxide phase.

• Korean Journal of Materials Research
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• v.6 no.10
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• pp.1043.2-1048
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• 1996

자기기록의 고밀도화로 인해 보자력(Hc)이 큰 자기기록매체가 필요하게 되었다. 고보자력매체에 신호를 충분히 기록하기 위해서는 보다 강한 자장이 필요하다. 이 때문에 포화자화(Ms)가 큰 재료가 필요하며 고주파 영역에서 실효투자율($\mu$eff)이 높아야 한다. Fe계 합금박막은 이에 적합한 재료이다. 본 연구에서는 Fe의 결정자기이방성에 영향을 미치는 Si과 Fe의 격자 변형을 유도할 수 있는 B를 첨가하였다. Fe-B-Si 계 박막을 질소분위기 중에서 RF Matnetron Sputter로 제작하여 연자기적 특성에 관하여 고찰하였다. Fe91.49B4.01Si4.50at% 박막은 35$0^{\circ}C$에서 1시간 열처리를 행함으로써 약 900(10MHz) 정도의 투자율과 7.6Oe의 보자력을 나타냈으며 포화자화는 1300emu/㎤를 얻었다.

• Journal of the Korean Magnetics Society
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• v.25 no.1
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• pp.4-9
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• 2015

This study was carried out to investigate a influence of humidity variation (%) on the magnetic properties and the surface flaws in the fabrication of Fe-based $Fe_{78}Si_9B_{13}$ amorphous alloy ribbon by Planar Flow Casting process. As a result, the size of the air pocket and the droplet which is observed in the contact surface and the free face of the amorphous alloy ribbon becomes large when the humidity increases and the size highly increases with the surface roughness at the same time. Especially, the surface roughness value which is made in the 65 % of the humidity is the lowest in the contact surface ($Ra=0.60{\mu}m$, $Rz=3.11{\mu}m$) and the free face ($Ra=0.47{\mu}m$, $Rz=3.00{\mu}m$). Also, in case of the soft magnetic property of the magnetic core which is made with the toroidal core of $23(OD)^*20(ID)^*20(H)$ size, in the sample of the amorphous alloy ribbon which is made in 65% of the humidity, the most excellent value is gained as $B_s(B_{700})=1.055T$, $H_c=0.083Oe$, permeability = 1,197 and core loss = 0.276W/kg.

• Korean Journal of Materials Research
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• v.6 no.11
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• pp.1061-1066
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• 1996

RF magnetron reactive sputtering법으로 Fe75.5Zr8.3N16.2/SiO2(250$\AA$) 다층 박막을 FeZrN의 두께를 변화시키면서 제조하고, 제조된 박막을 진공 열처리하여 열처리 온도에 따른 포화자화, 보자력, 고주파에서의 투자율 그리고 열적 안정성을 조사하였다. Fe75.5Zr8.3N16.2/SiO2(250$\AA$) 다층박막은 FeZrN의 두께가 800$\AA$이상일 때 좋은 연자성을 나타내었다. Fe75.5Zr8.3N16.2/SiO2(250$\AA$)다층 박막을 45$0^{\circ}C$로 열처리 했을 때 포화자속밀도(1.08 T), 보자력 0.41 Oe, 1 MHz에서의 실효 투자율은 3000이상의 연자성을 나타내었다. 그 이유는 X-선 회절 분석 결과 열처리에 의해서 ZrN 미결정이 석출하여 $\alpha$-Fe 결정 성장이 억제되어 우수한 연자기적 성질이 나타난다고 판단된다. 이때 $\alpha$-Fe 입자 크기는 40-50$\AA$, ZrN의 입자 크기는 10-15$\AA$이다. 그리고 실효 투자율의 주파수 의존성에서 단층막에서는 5 MHz 이상에서 실효 투자율이 급격히 감소하는 경향을 보였으나, 다층막에서는 40MHz까지 실효 투자율이 1600이 되어 고주파에서의 연자성이 개선되었다.

• Journal of the Korean Magnetics Society
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• v.6 no.5
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• pp.317-322
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• 1996

Thin films of Fe-Zr-N were fabricated by rf magnetron reactive sputtering method. The saturation magnetization and coercivity as functions of annealing temperature and partial pressure of nitrogen gas, effective permeability at high frequencies, and thermal stability were investigated. Magnetic softness was exhibited in the composition range of $Fe_{72-78}Zr_{7-10}N_{15-18}$ which was boundary between polycrystalline and amorphous structure. These films exhibited magnetic softness with saturation magentic flux density of 1.55 T and effective permeability of about 3000 at 1 MHz. These films also exhibited thermal stability by sustaining effective permeability of 2500 or above as the temperature was raised to $550^{\circ}C$. It is asswned that good magnetic softness is obtained because grain growth of $\alpha-Fe$ is prohibited due to the precipitation of ZrN nanocrystals. The grain sizes of $\alpha-Fe$ films were $40~50\AA$ and the grain sizes of ZrN nanocrystals were $10~15\AA$.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.952-957
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• 1994

Fe/Co and FeN/CoN multilayer films were prepared by using RF and DC magnetron sputter^ ing technique with Ar or a mixture of Ar and $N_{2}$ gas. Annealing treatment was carried out in a vacuum at temperatures between $100^{\circ}C$ and $500^{\circ}C$ for lhour. Saturation magnetization (MS) and coercivity (Hc) of Fe/Co mutilayer films were investigated as a function of Fe layer thickness and annealing temperature. Permeability ($\mu$) was also examined. Saturation magnetization of 1.8T and coercivity of 1.80e were obtained for the as-deposited Fe/Co($70 \AA /15 \AA$) multilayer film. The Coercivity(Hc) did not change from 1.8 Oe till the annealing temperature $250^{\circ}C$ and then increased rapidly at higher annealing temperatures above $300^{\circ}C$. Coercivity(Hc) measured for the as-deposited FeN/CoN multilayer film was 5 Oe. It decreased gradually with annealing up to $250^{\circ}C$, and then increased rapidly at higher tempera tures.

• Korean Journal of Materials Research
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• v.11 no.1
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• pp.39-43
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• 2001

Nanocrystalline Fe-Sm-O thin films were prepared by RF magnetron reactive sputtering method in $Ar+O_2$mixed atmosphere with the $O_2$content of 5%. The compositions of the thin films were changed by changing the number of $Sm_2O_3$ chips. The best soft magnetic properties of the thin film with the composition of $Fe_{83.4}Sm_{3.4}O_{13.2}$ were saturation flux density of 18 kG, coercivity of 0.82 Oe and effective permeability about 2,600 at 0.5~100 MHz, respectively. The electrical resistivity of Fe-Sm-O thin films was increased with increasing the amount of Sm and O elements which combined each other, the electrical resistivity of$Fe_{83.4}Sm_{3.4}O_{13.2}$ thin film was $130{\mu}{\Omega}cm$. In case of the small amount of Sm and O elements, the microstructures of Fe-Sm-O thin films showed a precipitated phase of $Sm_2O_3$ on the ${\alpha}-Fe$ phase. With the increase of the amount of Sm and O elements, the microstructures of the Fe- Sm-O thin films were changed into a mixed structure of ${\alpha}-Fe$ crystal-phase and Sm-oxide amorphous phase. The Fe-Sm-O thin films with Fe content in the range of 72~94 at% exhibited the quality factor (Q = $\mu$′/$\mu$") of 7~75 up to 50 MHz.