• 제목/요약/키워드: Saturation magnetization

검색결과 469건 처리시간 0.032초

FeCoB Films with Large Saturation Magnetization and High Magnetic Anisotropy Field to Attain High Ferromagnetic Resonance Frequency

  • Nakagawa, Shigeki;Hirata, Ken-Ichiro
    • Journal of Magnetics
    • /
    • 제18권2호
    • /
    • pp.155-158
    • /
    • 2013
  • FeCoB films were being prepared on a Ru underlayer by using the oblique incidence of sputtered and back-scattered particles which have a high in-plane magnetic anisotropy field $H_k$ above 400 Oe. It is suitable to attain such deposition condition when facing targets sputtering system. The in-plane X-ray diffraction analysis clarified that there is anisotropic residual stress which is the origin of the high in-plane magnetic anisotropy. The directional crystalline alignment and inclination of crystallite growth were also observed. Such anisotropic crystalline structures may affect the anisotropic residual stress in the films. The B content of 5.6 at.% was appropriate to induce such anisotropic residual stress and $H_k$ of 410 Oe in this experiment. The film with B content of 6 at.% possessed large saturation magnetization of 22 kG and high $H_k$ of 500 Oe. The film exhibited high ferromagnetic resonance frequency of 9.2 GHz.

Formulation and Magnetic properties of Sr-ferrite powders by Modified spray co-roasting (단순화된 분무열분해법을 이용한 Sr-ferrite 제조와 자기특성)

  • 김효준;조태식;남효덕;양충진
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 한국전기전자재료학회 1998년도 춘계학술대회 논문집
    • /
    • pp.49-52
    • /
    • 1998
  • Preparation of hexagonal strontium-ferrite by modified spray co-roasting(MSC:H) which is expected to shorkn the length of the process and to elevate the magnetic properties of hard ferrite was studied. We prapared $Fe_2O_3/SrCO_3$ mixture powders by MSCR after stirring ionized $FeCI_2$ in distilled water with solid state $SrCO_3$. And then calcined the mixture powders up to $1150^{\circ}C$ for Sr-ferrite powders It is possible to prepare hexaferrite powders with high saturation magnetization (Ms > 69 emu/g) , coercivity (Hc > 4000 Oe) The nlagnetic values of saturation magnetization iire higher than those achieved by the conventional technique.

  • PDF

Fabrication of Nanocrystalline FeCoTaN Magnetic Films Having High Saturation Magnetization and Excellent High Frequency Characteristics (고 포화 자화 및 우수한 고주파 특성을 가진 나노결정 FeCoTaN 박막의 제조)

  • J. M. Shin;Kim, J.;Kim, Y. M.;S. H. Han;Kim, H. J.
    • Proceedings of the Korean Magnestics Society Conference
    • /
    • 한국자기학회 2002년도 동계연구발표회 논문개요집
    • /
    • pp.214-215
    • /
    • 2002
  • High saturation magnetization (B$\_$s/) and excellent high frequency characteristics of magnetic thin films has been recognized as the most important requirement for further miniaturization and higher frequency operation in magnetic devices, such as magnetic heads and magnetic sensors. Up to now, Fe-X-N (X =Ti, Hf, and Al etc.) films with B$\_$s/ of 15 ∼ 19 kG and coercivity (H$\_$c/) of 0.5 ∼ 5.0 Oe have been successfully fabricated and proven to satisfy various requirements as a potential candidate for thin film head materials. (omitted)

  • PDF

Fabrication and Characterization of AlN films Containing Various Amounts of Co Content

  • Bae, Chang-Hwan;Han, Seung-Oh;Han, Cahng-Suk
    • Korean Journal of Metals and Materials
    • /
    • 제48권3호
    • /
    • pp.268-275
    • /
    • 2010
  • A new approach is described for preparing AlN thin films containing various amounts of Co content by using a two-facing targets type sputtering (TFTS) system. The deposited films were annealed isothermally at different temperatures and their microstructure, magnetic properties and resistivity were investigated. A small saturation magnetization ($4{\pi}Ms=0.52{\sim}0.85kG$) was observed irrespective of Co content in the asdeposited films. It was found that annealing conditions can control physical properties as well as the microstructure of the films. A high saturation magnetization (3.7 kG) and resistivity of $2200{\mu}{\Omega}-cm$ was obtained for AlN films containing 25 at.% Co.

Low Writing Field on Perpendicular Nano-ferromagnetic

  • Wibowo, Nur Aji;Rondonuwu, Ferdy S.;Purnama, Budi
    • Journal of Magnetics
    • /
    • 제19권3호
    • /
    • pp.237-240
    • /
    • 2014
  • For heat-assisted magnetic recording, magnetization reversal probabilities of nano-Pt/MnSb multilayer film with perpendicular magnetic anisotropy under thermal pulse activation were investigated numerically by solving the Landau-Lifshift Gilbert Equation. Magnetic parameters of nano-Pt/MnSb multilayer were used with anisotropy energy of $3{\times}10^5$ erg/cc and saturation magnetization of 2100 G, which offer more than 10 y data stability at room temperature. Scheme of driven magnetic field and thermal pulse on writing mechanism was designed closely to real experiment. This study found that the chosen material is potential to be used as a high density magnetic storage that requires low writing field less than two-hundreds Oersted through definite heating and cooling interval. The possibility of writing data with a zero driven magnetic field also became an important result. Further study is recommended on the thickness of media and thermal pulse design as the essential parameters of the reversal magnetization.

Effect of Magnetic Property Modification on Current-Induced Magnetization Switching with Perpendicular Magnetic Layers and Polarization-Enhancement Layers

  • Kim, Woo-Jin;Lee, Kyung-Jin;Lee, Taek-Dong
    • Journal of Magnetics
    • /
    • 제14권3호
    • /
    • pp.104-107
    • /
    • 2009
  • The effects of the magnetic property variation on current-induced magnetization switching in magnetic tunnel junction with perpendicular magnetic anistoropy (PMA) and the soft magnetic polarization-enhancement layers (PELs) inserted between the layers with PMA and the MgO layer was studied. A micromatnetic model was used to estimate the switching time of the free layer by different applied current densities, with changing saturation magnetization ($M_s$) of the PELs, interlayer exchange coupling between PMA layers and PELs. The switching time could be significantly reduced at low current densities, by increasing $M_s$ of PELs and decreasing interlayer exchange coupling.

CHARACTERIZATION OF MAGNETIZATION BEHAVIOR IN Co/Pd PERPENDICULAR ANISOTROPIC MULTILAYERS

  • Oh, Hoon-Sang;Joo, Seung-Ki
    • Journal of the Korean Magnetics Society
    • /
    • 제5권5호
    • /
    • pp.655-658
    • /
    • 1995
  • Magnetization behavior of sputter-deposited Co/Pd multilayers were characterized, and it has been found that even when the multilayers are sputtered at low pressure (10 mTorr), the coercivity of the multilayers can be increased to large extent without noticeable change of saturation magnetization by increasing the deposition pressure of Pd underlayer. It turned out that the surface topology of Pd underlayer gets rough as deposition pressure increases, which consequently affects the magnetization reversal mode of Co/Pd multilayers from domain wall motion to magnetic spin rotation. The enhancement of coercivity is attributed to the domain wall pinning effect which is comected with the surface roughness of Pd underlayer on which Co/Pd multilayers grow.

  • PDF

Modified Current Differential Relay for Transformer Protection Unaffected by Remanent flux (잔류자속에 무관한 변압기 보호용 수정전류차동 계전기)

  • 강용철;김은숙
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • 제53권9호
    • /
    • pp.500-506
    • /
    • 2004
  • This paper proposes a modified current differential relay for transformer protection unaffected by the remanent flux. The relay uses the same restraining current as a conventional relay, but the differential current is modified to compensate for the effects of the exciting current. To cope with the remanent flux, before saturation, the relay calculates the core-loss current and uses it to modify the measured differential current. When the core then enters saturation, the initial value of the flux is obtained by inserting the modified differential current at the start of saturation into the magnetization cure. Thereafter, the actual core flux is then derived and used in conjunction with the magnetization curve to calculate the magnetizing current. A modified differential current is then derived that compensates for the core-loss and magnetizing currents. The performance of the proposed differential relay was compared against a conventional differential relay. Results indicate that the modified relay remained stable during severe magnetic inrush and over-excitation because the exciting current was successfully compensated. This paper concludes by implementing the relay on a hardware platform based on a digital signal processor. The relay discriminates magnetic inrush and over-excitation from an internal fault and is not affected by the level of remanent flux.

Modified Current Differential Relay for $Y-{\Delta}$ Transformer Protection ($Y-{\Delta}$ 변압기 보호용 수정 전류차동 계전기)

  • Jin, En-Shu;Kang, Yong-Cheol
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • 제55권3호
    • /
    • pp.95-101
    • /
    • 2006
  • This paper proposes a modified current differential relay for $Y-{\Delta}$ transformer protection. The relay uses the same restraining current as a conventional relay, but the differential current is modified to compensate for the effects of the exciting current. A method to estimate the circulating component of the delta winding current is proposed. To cope with the remanent flux, before saturation, the core-loss current is calculated and used to modify the measured differential current. When the core then enters saturation, the initial value of the flux is obtained by inserting the modified differential current at the start of saturation into the magnetization cure. Thereafter, the core flux is then derived and used in conjunction with the magnetization curve to calculate the magnetizing current. A modified differential current is then derived that compensates for the core-loss and magnetizing currents. The performance of the proposed differential relay was compared against a conventional differential relay. Test results indicate that the modified relay remained stable during severe magnetic inrush and over-excitation, because the exciting current was successfully compensated. This paper concludes by implementing the relay on a hardware platform based on a digital signal processor. The relay does not require additional restraining signal and thus cause time delay of the relay.

Modified Current Differential Relay for Y-$\Delta$ Transformer Protection (Y-$\Delta$ 변압기 보호용 수정 전류차동 계전기)

  • Kang, Yong-Cheol;Jin, En-Shu;Lee, Byung-Eun
    • Proceedings of the KIEE Conference
    • /
    • 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
    • /
    • pp.9-13
    • /
    • 2004
  • This paper proposes a modified current differential relay for Y-$\Delta$ transformer protection. The relay uses the same restraining current as a conventional relay, but the differential current is modified to compensate for the effects of the exciting current. A method to estimate the circulating component of the delta winding current is proposed. To cope with the remanent flux, before saturation, the core-loss current is calculated and used to modify the measured differential current. When the core then enters saturation, the initial value of the flux is obtained by inserting the modified differential current at the start of saturation into the magnetization cure. Thereafter, the core flux is then derived and used in conjunction with the magnetization curve to calculate the magnetizing current. A modified differential current is then derived that compensates for the core-loss and magnetizing currents. The performance of the proposed differential relay was compared against a conventional differential relay. Test results indicate that the modified relay remained stable during severe magnetic inrush and over-excitation because the exciting current was successfully compensated. The relay correctly discriminates magnetic inrush and over-excitation from an internal fault and is not affected by the level of remanent flux.

  • PDF