• Title, Summary, Keyword: $Co_2Z$ ferrite

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Impedance Matching of Electrically Small Antenna with Ni-Zn Ferrite Film

  • Lee, Jaejin;Hong, Yang-Ki;Lee, Woncheol;Park, Jihoon
    • Journal of Magnetics
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    • v.18 no.4
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    • pp.428-431
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    • 2013
  • We demonstrate that a partial loading of $Ni_{0.5}Zn_{0.5}Fe_2O_4$ (Ni-Zn ferrite) film remarkably improves impedance matching of electrically small $Ba_3Co_2Fe_{24}O_{41}$ ($Co_2Z$) hexaferrite antenna. A 3 ${\mu}m$ thick Ni-Zn ferrite film was deposited on a silicon wafer by the electrophoresis deposition process and post-annealed at $400^{\circ}C$. The fabricated Ni-Zn ferrite film has saturation magnetization of $268emu/cm^3$ and coercivity of 89 Oe. A partial loading of the Ni-Zn ferrite film on the $Co_2Z$ hexaferrite helical antenna increases antenna return loss to 24.7 dB from 9.0 dB of the $Co_2Z$ antenna. Experimental results show that impedance matching and maximum input power transmission to the antenna without additional matching elements can be realized, while keeping almost the same size as the $Co_2Z$ antenna size.

The Effect of Ba and Fe Concentration on Soft Magnetic Properties of Z-Type Barium Ferrite (Z-Type 바리움 페라이트 분말의 연자성 특성에 미치는 Ba 및 Fe 농도의 영향)

  • Cho, Kwang-Muk;Nam, In-Tak
    • Journal of the Korean Magnetics Society
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    • v.19 no.1
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    • pp.12-16
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    • 2009
  • Z-type barium ferrite [($Ba_{3}Co_{0.8}Zn_{1.2}Fe_{24}O_{41}$, $Ba_{3+{\delta}}Co_{0.8}Zn_{1.2}Fe_{24}O_{41}$ ${\delta}$ = 3, 5, 7, 13 wt%. $Ba_{3}Co_{0.8}Zn_{1.2}Fe_{24+{\delta}}O_{41}$ ${\delta}$ = 5, 7, 10 wt% )] were synthesized using co-precipitation method. The microstructure and magnetic properties of synthesized particles were investigated. In all prepared particles M-type Ba ferrite is identified with Z-type Ba ferrite together. It is found that particles having 7 wt% for Ba and 5 wt% for Fe excess addition revealed high saturation magnetization, respectively. All synthesized particles showed relatively high coercivity for device application. This result may be attributed to the contribution of M-type Ba ferrite. Ba and Fe excess addition was not affected to the structural change of CoZnZ Ba ferrite. The certain amount of excess additions of Ba and Fe and the 2 step heat-treatment may be beneficial to the improvement of soft magnetic properties of Z-type barium hexa-ferrite

Structural and Magnetic Properties of Z-type Barium Ferrite (Z-type 바리움 페라이트의 구조 및 자기적 성질)

  • Nam, In Tak
    • Journal of Industrial Technology
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    • v.28 no.A
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    • pp.119-123
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    • 2008
  • Structural and magnetic properties of $CO_{1-x}Zn_xZ$ ($Ba_3Co_{1-x}Zn_xFe_{24}O_{41}$) hexa-ferrite are studied using XRD, VSM and SEM, respectively. Powder was prepared from co-precipitation and firstly heat treated at $1350^{\circ}C$ for 6 hours in $O_2$ atmosphere. Second heat treatment was performed at 900, 1000, $1100^{\circ}C$ for 6 hours in air, respectively. Saturation magnetization value of first heat treated powder is acceptable and coercivity is high for applying to device. These result may be originated from incomplete formation reaction from M and Y phases to Z phase. Second heat treatment leads to small value of coercivity.

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Study on Low-Temperature sintering of Co2Z type Ba ferrites for chip inductor (Chip inductor용 Co2Z type Ba-ferrite의 저온소결에 관한 연구)

  • 조균우;한영호;문병철
    • Journal of the Korean Magnetics Society
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    • v.12 no.5
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    • pp.195-200
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    • 2002
  • Low temperature sintering of Co$_2$Z type Ba ferrites with various oxide additives has been studied. Co$_2$Z phase was obtained by 2 step calcination and XRD peaks showed a good agreement with the peaks of the standard Co$_2$Z phase, except for some minor extra peaks. ZnO-B$_2$O$_3$ glass, ZnO-B$_2$O$_3$ and CuO, ZnO-B$_2$O$_3$ and Bi$_2$O$_3$, and ZnO-Bi$_2$O$_3$ glass were added to lower sintering temperatures. Specimens were sintered at the temperature range between 900 $^{\circ}C$ and 1000 $^{\circ}C$. In the single addition of ZnO-B$_2$O$_3$ glass, the specimen with 7.5 wt% showed the highest shrinkage. Specimens with complex addition of ZnO-B$_2$O$_3$ glass with CuO or Bi$_2$O$_3$ showed higher shrinkages and initial permeabilities than single addition of ZnO-B$_2$O$_3$ glass. Shrinkages and initial permeabilities of the specimens with ZnO-Bi$_2$O$_3$ glass were higher than those of ZnO-B$_2$O$_3$ glass addition.

Formation of Hexagonal Ferrite $Co_2$Z(${Ba_3}{Co_2}{Fe_{24}}{O_{41}}$) Prepared by Coprecipitation-oxidation Method (공침산화법에 의한 육방정 페라이트 $Co_2$Z(${Ba_3}{Co_2}{Fe_{24}}{O_{41}}$)의 생성)

  • 신형섭
    • Journal of the Korean Ceramic Society
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    • v.38 no.11
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    • pp.1023-1029
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    • 2001
  • Hexagonal ferrite $Co_2$Z(B $a_3$ $Co_2$F $e_{24}$ $O_{41}$ ) was prepared by various coprecipitation-oxidation methods. The formation of $Co_2$Z was studied in order to determine the optimal method. The $Co_2$Z composition hydroxides were prepared with the different oxidation and precipitation from the aqueous solution of $Ba^{2+}$, $Co^{2+}$ and F $e^{2+}$ chloride mixture. The coprecipitates were heat-treated at various temperatures, and their formation phases and microstructures were investigated from the analyses of DTA/TGA, powder XRD and SEM. The $Co_2$Z phase was observed in the case where the precursor will have the amorphous like oxyhydoxide($\delta$-FeOOH), and formed from $Ba_3$F $e_{32}$ $O_{51}$ , BaF $e_{12}$ $O_{19}$ (M-type) and $Ba_2$ $Co_2$F $e_{12}$ $O_{22}$ (Y-type). The $Co_2$Z was synthesized by the heat-treatment of the coprecipitate, which was prepared from the precipitation after oxidizing the chloride mixed solution, above 110$0^{\circ}C$.EX>.

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Microwave Properties of Ba-$Co_2Z$ Ferrite with Zn addition (Zn 첨가에 따른 Ba-$Co_2Z$ 페라이트의 마이크로파 특성)

  • Kim, Jae-Sik;Choi, Eui-Sun;Ryu, Ki-Won;Koh, Jung-Hyuk;Lee, Young-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.299-299
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    • 2010
  • In this study, microwave properties with compositions and frequency of the $Ba_3Co_2Fe_{24}O_{41}$ ceramics with Zn substitution for Co were investigated. From the XRD patterns, hexagonal structure of Z-type phase was existed as main phase. Diffraction peaks of Z-type phase were shifted to lower angle by Zn substituted for Co site. The permittivity was increased with Zn additions. In all composition, loss tangent of permittivities were increased with frequency. Permeability and magnetic resonance frequency were increased with Zn additions. Permeability was increased and loss tangent of permeability was decreased rapidly over 600 MHz~800 MHz. The loss tangent of permeability did not changed with composition ratio. In the case of $Ba_3Co_{1.6}Zn_{0.4}Fe_{24}O_{41}$ ceramics sintered at $1250^{\circ}C$ for 3 hours, the permittivity, loss tangent of permittivity, permeability and loss tangent of permeability were 28.277, 0.193, 22.992 and 0.065 at 310 MHz, respectively.

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Stydies on the Hexagonal Ferrites(II) The Nagnetostricton pf Ferroxplana $Co_{1-x}Zn_xZ$($BA_3Co_{2(1-x)}Zn_{2x} Fe_{24}O_{41}$)) (Hexagonal Ferrite 에 관한 연구(II) Ferroxplana $Co_{1-x}Zn_xZ$($BA_3Co_{2(1-x)}Zn_{2x} Fe_{24}O_{41}$)의 Magnetostriction)

  • 김태옥
    • Journal of the Korean Ceramic Society
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    • v.13 no.4
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    • pp.5-8
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    • 1976
  • Both oriented and non-oriented ferroxplana $Co_{1-x}Zn_xZ(Ba_3Co_{2(1-x)}Zn_{2x} Fe_{24}O_{41})$ with x=0.00, 0.45 were prepared by conventional ceramic method. The magnetostrictions of thus prepared specimens were measured by use of the three terminal capacitor device at room temperature. The magnitude of measured values was approximately five times greater than that of ZnY ferroxplana. The easy-magnetization plane at room temperature of both CoZ and Co0.55 $Zn_{0.45}$Z was their basal plane. The magentostrictions in the basal plane and the other planes showed saturated values at magnetic field intensity of about 2Koe and 4Koe, respectively. The magnetostriction constants $K_1, \; K_2, \;K_3\; and\; K_4$ for CoZ were -2.4, -10.5, -5.9 and -45.2$\times10^{-6}$ , while those for $Co_{0.55}Zn_{0.45}Z$ were +0.1, -1.2, -6.3 and -39.0$\times$10^{-6}, , respectively.

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Crystal and Block Structures of Hexagonal Ferrites (육방정 페라이트의 결정과 Block 구조)

  • Shin, Hyung-Sup
    • Journal of the Korean Ceramic Society
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    • v.49 no.3
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    • pp.205-215
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    • 2012
  • It has been studied the crystal and block structures of the hexagonal ferrites with M, W, Y and Z types prepared by various coprecipitation-oxidation method. The structures have been refined with a Rietveld analysis of the powder X-ray diffraction pattern with high precision ($R_{WP}$ <0.09, $R_I$ <0.03). The density difference between the S-blocks was proportioned to the cobalt contents in hexagonal ferrites, but that between the R or T-blocks was relatively small. Compared with the blocks and cation-oxygen polyhedra in BaM ($BaFe_{12}O_{19}$), those were bulky to the normal direction for the c-axis in $Co_2W$ ($BaCo_2Fe_{16}O_{27}$) and to the parallel direction for the c-axis in $Co_2Y$ ($Ba_2Co_2Fe_{12}O_{22}$) and $Co_2Z$ ($Ba_3Co_2Fe_{24}O_{41}$). The S-blocks of $Co_2W$, $Co_2Y$, and $Co_2Z$ were unstable and distorted. Because the T-block of $Co_2Z$ was unstable, the T-block was decomposed into the Ba-rich phase and $Co_2W$ at high temperatures above $1200^{\circ}C$. A standard powder X-ray diffraction pattern for $Co_2Z$ was proposed as well.

The effect of $Co_{3}O_{4}$additives on the magnetic Properties of $Ni_{0.8-xZn_{0.2+x}Fe_{2}O_4}$ ($Co_{3}O_{4}$첨가제 변화에 따른 $Ni_{0.8-xZn_{0.2+x}Fe_{2}O_4}$의 자기적 특성)

  • 이선학;오영우;김덕훈;김현식;이해연;송재성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.331-334
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    • 2001
  • In this study, the magnetic properties for Ni-Zn ferrite were investigated as the function of $Co_3$ $O_4$ additive contents which was predicted to improve the resonance frequency. Toroid specimens with the composition of N $i_{0.8-x}$Z $n_{0.2+x}$F $e_2$ $O_4$(x = 0, 0.05, 0.1, 0.15) ferrites were preparation by conventional ceramic processing technique. The maximum resonance frequency of 19.905 MHz and the permeability of 90.88 in 10 MHz were attained to the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$with $Co_3$ $O_4$0.3 wt%. Both of the permeability in 10 MHz and the resonance increased to 107.11 and 19.005 MHz respectively for the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$with $Co_3$ $O_4$wt% than the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$/ with the free $Co_3$ $O_4$composition.composition.

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