• Title/Summary/Keyword: Saturation field

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A Computational Method to Consider the Saturation of Magnetic Field In a High Density Recording Head

  • Park, Gwan-Soo
    • Journal of Magnetics
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    • v.8 no.4
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    • pp.164-168
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    • 2003
  • In high density recording system, the recording head field on a medium should be focused in small bit area and should have a sufficient value to overcome the medium coercivity, which resulted in head saturation. In this paper, an efficient method to access the head field and field gradient considering head saturation is presented. The magnetic vector potential on the head surface is pre-calculated considering head saturation in several cases and accumulated into database. The head field on the recording media is easily produced solving Laplace equation using accessed magnetic vector potential boundaries. The computed head field is compared with a quantified magnetic force microscopy measurement.

Lateral Electric Field Model and Degradation Mechanism of surface-Channel PMOSFET's (SC PMOSFET의 수평 전개 모델과 노쇠화 메카니즘)

  • 양광선;박종태;김봉렬
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.1
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    • pp.54-60
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    • 1994
  • In this paper, we present the analytical models for the change of the lateral electric field distribution and the velocity saturation region length with the electron trapping of stressed SC-PMOSFET in the saturation region. To derive the hot-electron-induced lateral electric field of stressed SC-PMOSFET. Ko's pseudo two dimensional box model in the saturation region which illustrates the analysis of the velocity saturation region is modified under the condition of electron trapping in the oxide near the drain region. From the results, we have the following lateral electric field in the y-direction, that is, E(y) ES1satT.cosh(y/l) qNS1tT.sinh(y/l)/lCox. It is shown that the trapped electrons influence the field in the drain region. decreasing the lateral electric field. Calculated velocity saturaion length increases with the trapped electrons. increasing the drain current of stressed SCPMOSFET. This results well explain the HEIP phenomenon of PMOSFET's.

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Analysis of a Crack in Ferroelectric Ceramics Subjected to Electric Fields (전기장을 받는 강유전체 세라믹내의 균열 해석)

  • 범현규;김인옥
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.6
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    • pp.138-144
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    • 2003
  • A crack in a ferroelectric ceramic subjected to an electric field is analyzed. The boundary of the electrical saturation zone is estimated based on the finite-width saturation zone model, which is analogous to a finite-width Dugdale zone model for mode III. It is shown that the shape and size of the switching zone depends strongly on the boundary of the electrical saturation zone and the ratio of the coercive electric field to the yield electric field. The crack tip stress intensity factor under small scale conditions is evaluated by employing the model of electric nonlinear domain switching. It is found that fracture toughness of the ferroelectric material may be increased or decreased depending on the material property of electrical nonlinearity.

The study on effects of porosity grain size, magnetization and anisotropy field on the properties of ferromagnetic resonance (다결정 Mg-페라이트의 기공율, 입경, 포화 자화 및 이방성 자기장이 강자성 공명 특성에 미치는 영향 연구)

  • 김진호;주승기;최덕균
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.1
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    • pp.97-102
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    • 1995
  • The ferromagnetic resonance properties of Mg ferrites which have various porosity grain size, and saturation magnetization are measured at one frequency. This allows a determination of the anisotropy field(Ha). The saturation magnetization multiplied by porosity is the resonance magnetic field. As the saturation magnetization increases, the linewidth decerases due to decrement of magnetic inhomogenity in sample. the porosity is a major factor broadening the linewidth for Mg ferrite when porosity is more thatn 6%, and the anisotropy field is dominant when porosity is less than 6%.

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Effect of Fcrromagnetic Layer and Magnetoresistance Behavior of Co-Evaporated Ag-CoFe Nano-Granular Alloy Films (Ag - CoFe 합금박막의 자기저항 및 강자성 상하지층의 효과)

  • 김용혁;이성래
    • Journal of the Korean Magnetics Society
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    • v.7 no.6
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    • pp.308-313
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    • 1997
  • The magnetoresistance (MR) and the saturation field behavior of the CoFe-Ag nano granular films as a function of the ferromagnetic underlayer and overlayer materials were investigated. The maximum MR ratio of 25.7 % and the saturation field of 2.1 kOe in the as-deposited 3000 $\AA$ $(Co_{92}Fe_8)_{31}Ag_{69}$ single alloy films at room temperature were obtained. The MR ratio and the saturation field of the 100 $\AA$ alloy film were 1.2 % and 5.2 kOe, respectively. Those of the sandwiched alloy films of 200 $\AA$ thick with the Fe under and overlayer of 100 $\AA$ were 11 % and 1.8 kOe respectively. The reduction of saturation field in the sandwiched alloy films is due to the exchange coupling between the ferromagnetic layers and the alloy layer. Among the Fe and FeNi, the more effective materials to reduce the saturation field of the sandwiched alloy films was Fe.

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Giant Magnetoresistance Behavior and the Effect of Ferromagnetic Layer on the Co-Ag Nano-granular Alloy Films (Co - Ag 합금박막의 거대자기저항 및 강자성 상하지층의 효과)

  • 김용혁;이성래
    • Journal of the Korean Magnetics Society
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    • v.7 no.1
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    • pp.31-37
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    • 1997
  • The magnetoresistance and the saturation field behavior of the Co-Ag nano granular films as a function of the composition and the ferromagnetic underlayer and overlayermaterials were investigated. The maximum magnetoresistance of 23% and the saturation field of 2.3 kOe at room temperature were obtained in the as-deposited 3000$\AA$ $Co_{30}Ag_{70}$ single alloy films. The magnetoresistance and the saturation field of 100$\AA$ $Co_{30}Ag-{70}$ alloy film were 3.65 % and 3.0 kOe respectively. Those of the sandwiched films with 200$\AA$ Fe were 3.3 % and 1.23 kOe respectively. The saturation field of the sandwiched alloy films could be reduced by the exchange coupling between the ferromagnetic layers and the alloy layer. The effective depth of the exchange coupling was approximately 150$\AA$ in each Fe layer. Among the Fe, Co, and FeNi, the most effective materials to reduce the saturation field of the sandwiched alloy films was Fe.

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Water Requirement of Twist Peppers in Greenhouse (온실 재배 꽈리고추의 필요수량)

  • 윤용철
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.42 no.4
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    • pp.59-66
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    • 2000
  • This study was carried out to investigated the water requirement of twisted sweet peppers which are cultivated in a green house. The meteorological conditions during the experiment period was close to that of normal year except the temperature and relative humidity. The growth status was improved with the increased saturation ratio. The range of the variation of daily water requirement were very large. The peak consumption occurred in the early August. And the higher saturation ratio resulted in higher water requirement. The total water requirement were about 57.180g/d/plant for pot with 100% (P100) of saturation , about 38.700g/d/plant for pot with 80%(P80) of saturation , about 23,720g/d/plant for pot with 60%(P60) of saturation, and about 53, 390g/d/plant for field cultivation in the green house, respectively. The water requirement was correlated with average ambient temperature and growing status, while no significant correlation were found between water requirement and minimum relative humidity or intensity of solar radiation. And the higher correlation was shown as the saturation ratio was increased. The transpiration coefficients of twisted sweet pepper were 378.0g/g for field cultivation in the green house, 363.3g/g for P100, 338.7g for P80 which was the smallest among pot cultivation , and 472.1g/g for P60 , respectively.

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A Study on the Oxygen Saturation Level Changes in the Blood Exposed to the Static Magnetic Field (자속에 노출된 인체의 혈중 산소 포화농도의 변화에 관한 연구)

  • Jung, Yong-Chul;Lee, Dong-Hoon
    • Journal of the Korean Society of Safety
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    • v.22 no.6
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    • pp.87-90
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    • 2007
  • The effects of static magnetic field on the human biological system are becoming increasingly more important with the adaption of static magnet in the medical community. It is the goal of this paper to review the effects of static magnetic fields on oxygen saturation level in blood. The results of this paper show that the oxygen saturation level increased in the blood in index finger when the static magnetic dipole was fitted on index finger.

Observation of saturation transfer characteristics in solution processed vertical organic field-effect transistors (VOFETs) with high leakage current

  • Sarjidan, M.A. Mohd;Shuhaimi, Ahmad;Majid, W.H. Abd.
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1415-1421
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    • 2018
  • Unlike ordinary organic field-effect transistors (OFETs), saturation current is hardly to be found in vertical OFETs (VOFETs). Moreover, the fabrication process of patterned sourced for VOFETs is quite complex. In this current work, a simple solution processed VOFET with directly deposited intermediate silver source electrode has been demonstrated. The VOFET exhibits a high leakage current that induces an inversion polarity of its transistor behavior. Interestingly, a well-defined saturation current was observed in the linear scale of transfer characteristic. The VOFET operated with high-current density > $280mA/cm^2$ at $V_d=5V$. Overview potential of the fabricated device in display application is also presented. This preliminary work does open-up a new direction in VOFET fabrication and their application.

THE EFFECT OF OVER AND UNDERLAYER ON THE MAGNETORESISTANCE IN Co-Ag NANO-GRANULAR ALLOY FILMS

  • Kim, Yong-Hyuk;Lee, Seong-Rae
    • Journal of the Korean Magnetics Society
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    • v.5 no.5
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    • pp.451-455
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    • 1995
  • The composition and thickness dependence and the ferromagnetic under- and overlayer effect on the magnetoresistance ratio and saturation field of the Co-Ag nano-granular films were investigated. The maximum magnetoresistance (23% at R.T.) in the as-deposited state was obtained in the $3000{\AA}$ $Co_{30} Ag_{70}$ bare alloy film. As the thickness of the alloy films decreased below $500{\AA}$, the MR ratio decreased because of the resistivity increase and the non-uniform film formation. We showed that the ferromagnetic over- and underlayer could reduce the saturation field of the nano-granular films via exchange coupling effect. The magnetoresistance and the saturation field of the $100{\AA}$ alloy film were 3.65 % and 2.85 kOe respectively and those of the under- and overlayered alloy films with $200{\AA}$ Fe were 3.3 % and 1.23 kOe respectively.

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