• Title, Summary, Keyword: Mn-Zn Ferrite

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Coating Effects on Electromagnetic Wave Absorbers Prepared with Mn-Zn Ferrites

  • Song Jae-Man;Kim Dong-Il;Che Seung-Hun;Choi Yun-Seok;Kim Ki-Man;Rhyu Keel-Soo
    • Journal of electromagnetic engineering and science
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    • v.5 no.4
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    • pp.161-165
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    • 2005
  • We prepared Mn-Zn ferrite Electromagnetic(EM) wave absorbers. The Mn-Zn ferrite EM wave absorbers were coated with Sr ferrite powders and $Al(OH)_3$ powders. The coated Mn-Zn ferrite EM wave absorbers show improved absorption compared with non-coated Mn-Zn EM wave absorbers.

Magnetic and Electrical Properties of Mn-Zn Ferrite Thin Films Deposited by Ion Beam Sputtering (이온빔 스퍼터링에 의해 증착된 Mn-Zn 페라이트 박막의 자기 및 전기적 특성)

  • 조해석;하상기;이대형;주한용;김형준;김경용;제해준;유병두
    • Journal of the Korean Ceramic Society
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    • v.32 no.3
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    • pp.313-320
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    • 1995
  • We investigated the preferred orientation, electrical and magnetic properties of the Mn-Zn ferrite thin films deposited on SiO2/Si(100) by ion beam sputtering. The Cu-added Mn-Zn ferrite thin films had a preferred orientation of (111) with a weak orientation, (311). While the Zn-added one had a strong (111) preferred orientation. The saturation magnetization of the Cu- or Zn-doped Mn-Zn ferrite films increased with increasing substrate temperature (Ts) due to the increase of grain size and the enhancement of crystallinity. For the same reason the coercivity of Cu- or Zn-doped Mn-Zn ferrite films deposited at low Ts increased with increasing Ts, but those of the films deposited at high Ts slightly decreased not only because the defect density of the films decreases but because more grains have multi-domains with increasing Ts. The resistivity of Cu- or Zn-added Mn-Zn ferrite thin fims measured by complex impedance method decreased with increasing Ts due to the ehhancement of crystallinity as well as due to the increase of grain size.

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A Study on the magnetic properties of Mn-Zn Ferrite (Mn-Zn Ferrite의 자기적 특성에 관한 연구)

  • Kim Do-Hwan;Choi Young-Ji;Kwon Oh-Heung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.898-901
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    • 2006
  • In this paper, effect of ceramic processing was investigated on the magnetic properties of low loss Mn-Zn ferrite. High frequency characteristics, high saturated magnetic flux density and high magnetic permeability and low magnetism loss are required for the development of Mn-Zn ferrite, which is parts in the communication. therefore, in order to improve Mn-Zn ferrite with a high frequency , it is important to have a minimal change of particles and to control the eddy current loss caused by high resistance of the stratum of particles and to reduce the hysteresis loss by uniform change of detailed structure. In this paper, we added $V_2O_5\;and\;CaCo_3$ to Mn-Zn Ferrite to achieve a high efficiency, low loss core material. The compositions are MnO : ZnO : $Fe_2O_3$ = 21 : 10 : 69 mol%. They were sintered at $1250^{\circ}C$ for Three hours. Initial permeability was measured at 0.1MHz. At 50mT, Power loss was measured by temperature changing at 100kHz.

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Preparation for Mn-Zn Ferrite Soft Magnetic Underlayer Perpendicular Magnetic Recording Disk using Mn-Zn-Fe-O Metal Target (Mn-Zn-Fe-O 금속타깃을 이용한 수직자기기록디스크의 하지연자성층용 Mn-Zn ferrite 박막제작)

  • Kong, Sok-Hyun;Kim, Kyung-Hwan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.9
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    • pp.883-887
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    • 2006
  • In order to attain high-rate deposition of Mn-Zn ferrite thin film for soft magnetic underlayer in perpendicular magnetic recording media, a reactive sputtering using powder-metal targets under the mixture gas of Ar and $O_{2}$ was performed. It was succeeded that Mn-Zn ferrite films with (111) crystal orientation were deposited on Pt(111) underlayer without any annealing process. The film revealed 3.4 kG of 4 ${\pi}Ms$, 70 Oe of coercivity. The deposition rate of the new method was 16 times as high as that of the conventional method using ferrite target.

Microwave Absorber Prepared by Using the Wasted Mn-Zn Ferrite and the Cement (Mn-Zn ferrite 廢棄物과 시멘트를 이용한 電波吸收體)

  • 조완식;김종오
    • Journal of the Korean Institute of Resources Recycling
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    • v.9 no.6
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    • pp.31-35
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    • 2000
  • The complex permeability, the complex permittivity and the reflection loss are investigated in the composite microwave absorbers which are mixed with the wasted Mn-Zn ferrite and the industrial cement. The cement has larger the complex permittivity than that of the rubber. The complex permittivity is decreasing with the increment of the mixing ratio of Mn-Zn ferrite to cement (F/C in weight) and the complex permeability is increasing with the increment of F/C. The maximum reflection loss is above -40 dB at all samples. The matching frequency is in the range of 1.3 GHz to 2.9 GHz and is decreasing with the increment of F/C from 1 to 3. The matching thickness is increasing with the increment of F/C. The wasted Mn-Zn ferrite and the cement is very useful material for the composite microwave absorber.

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NiZn Ferrite Coating for Electrical Insulation of MnZn Ferrite Cores

  • Kitamoto, Y.;Yajima, H.;Nakayama, Y.;Abe, M.
    • Journal of the Korean Ceramic Society
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    • v.38 no.6
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    • pp.506-508
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    • 2001
  • The ferrite plating with applying power ultrasound waves of 19.5 kHz and 600W enabled us to encapsulate entirely MnZn ferrite cores for transformers with Ni$\sub$x/Zn$\sub$y/Fe$\sub$3-x-y/O$_4$coating. Supplying a NH$_4$OH solution during the plating broke the limit of the solubility of Ni ions to ferrite-plated films. The electrical resistivity of the NiZn ferrite coating increased with increasing the Ni and Zn content, reaching 2.3${\times}$10$\^$5/Ωcm at the composition of Ni$\sub$0.24/Zn$\sub$0.30/Fe$\sub$2.46/O$_4$. The saturation magnetization was 540 emu/㎤. As a result, the MnZn ferrite cores were successfully encapsulated with the NiZn ferrite coatings for an insulation layer.

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Development of EM Wave Absorber for Suppression Noise from PCB Using Sendust and Mn-Zn Ferrite (Sendust와 Mn-Zn Ferrite를 이용한 PCB로부터의 전자파 방사 억제용 전파흡수체 개발)

  • Yoon, Sang-Gil;Kim, Dong-Il;Song, Young-Man;Park, Soo-Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.2
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    • pp.244-249
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    • 2008
  • In this paper, we designed and fabricated the EM wave absorber consists of Sendust and Mn-Zn ferrite for suppressing EM wave noise from PCB in ISM(Industrial, Scientific and Medical) band of 2.4 GHz. We fabricated several samples in different ratios of Sendust to Mn-Zn ferrite with CPE(Chlorinated Ploy-ethylene) as binder and confirmed that optimum composition ratio of absorbing materials was Sendust. Mn-Zn ferrite : CPE=70:5:20 wt.%. The absorbing abilities were simulated according to different thickness of EM wave absorber as the function of material constants calculated by measured data. Measured absorption ability was analyzed and compared with simulated result. The simulated result agree well with the measured ones. As a result, the developed EM wave absorber with thickness of 0.85 mm has absorption ability of 5.4 dB at 2.4 GHz and over 3 dB in frequency rage of 1.4$\sim$4.1 GHz.

Effects of Ultrasonic Energy on Mn-Zn Ferrite Powder Behavior (초음파 에너지가 mn-Zn Ferrite 분체에 미치는 영향)

  • 이경직;이대희;이석기;이병교
    • Journal of the Korean Ceramic Society
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    • v.36 no.7
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    • pp.751-755
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    • 1999
  • Effect of ultrasonic-wave irradiation on the Mn-Zn ferrite powder suspension prepared by solid-state reaction and alcoholic dehydration methods was investigated. Size distribution and morphology of the powders prepared at different temperature were examined as a function of irradiation time. It was observed that the powders were reduced in size by ultrasonic energy through distinct routes.

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Electical and Electomagnetic wave Absorbing Properties of MnZn Ferrite-Rubber Composites in Microwave Frequencies (MnZn계 페라이트-고무 복합체의 마이크로파대역에서의 전기적 특성 및 전자파 흡수 특성)

  • 김호철;이병택;정연춘;엄진섭
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.4 no.2
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    • pp.41-47
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    • 1993
  • Electrical and electromagnetic wave absorbing properties of MnZn ferrite-rubber composites have been examined for varying the volume fraction of ferrite powder from 0.1 to 0.4 in the frequency range between 1-10 GHz. As the volume fraction of MnZn ferrite increased, the complex permittivity and permeability of composite increased. The peak of reflection loss at the frequency corresponding to 1/4 wavelength shifts to lower frequency, and shifts to lower frequency as the thickness of absorber increased. We show that for the ferrite-rubber composites the volume fraction of ferrite should be controled to obtain the absorbing properties required in given frequency range.

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