Journal of the Magnetics Society of Japan
Online ISSN : 1880-4004
Print ISSN : 0285-0192
ISSN-L : 0285-0192
Search
Advanced search
OR
Browse
Search
Volume 22, Issue 7
Displaying 1-3 of 3 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
Contributed Paper
  • Loss Analysis of Ferrite Cores, Using the Finite Element Method and the Dynamic Magnetic Loss Parameter
    H. Saotome, K. Tachibana
    1998 Volume 22 Issue 7 Pages 1144-1149
    Published: 1998
    Released on J-STAGE: June 29, 2007
    DOIhttps://doi.org/10.3379/jmsjmag.22.1144
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    Finite element analysis using the dynamic magnetic loss parameter was carried out, in order to evaluate the power loss of Mn-Zn ferrite cores. The accuracy of the numerical analysis was verified by comparing the numerically computed power loss with the analytical solutions at 100 kHz, 200 kHz, 1 MHz, and 2 MHz. The frequency characteristics of the computed core loss coincide with the measured ones. Finite element analysis taking account of the dielectric characteristics of Mn-Zn ferrites clarified the mechanism of the power loss dependence on the core dimensions. The analysis showed that the displacement current in a core causes a magnetic field opposite to the exciting magneto-motive force in a high-frequency region.
    View full abstract
    Download PDF (495K)
  • Tunnel Magnetoresistance for Ferromagnetic Tunnel Junctions: Dependence on Bias Voltage and Barrier Height
    T. Kishi, K. Inomata
    1998 Volume 22 Issue 7 Pages 1150-1153
    Published: 1998
    Released on J-STAGE: June 29, 2007
    DOIhttps://doi.org/10.3379/jmsjmag.22.1150
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    The transport properties of ferromagnetic tunnel junctions are investigated. The tunneling currents are calculated on the basis of a Tsu-Esaki-type equation that is extended to a spin-polarized system. The tunnel magnetoresistance decreases with increasing bias voltage, because of the energy dependence of the spin-dependent transmission coefficients. Junctions with different barrier widths show a similar decrease in the tunnel magnetoresistance. The tunnel magnetoresistance as a function of the barrier height increases for a lower barrier height, whereas, it oscillates for a negative barrier height.
    View full abstract
    Download PDF (275K)
  • Digital M-H Loop Tracer for Soft-Magnetic Thin Films
    X. Jiang, T. Suzuki
    1998 Volume 22 Issue 7 Pages 1154-1159
    Published: 1998
    Released on J-STAGE: June 29, 2007
    DOIhttps://doi.org/10.3379/jmsjmag.22.1154
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    Analysis of the measuring sensitivity of a conventional M-H loop tracer revealed that the sensitivity is limited by undesirable signals, caused by imbalance of a pick-up coil pair, use of a non-ideal electronic integrator, and/or the presence of ambient magnetic or conductive bodies. Most of these noises are periodic and synchronized with the exciting magnetic field at 50-60 Hz. This paper proposes a new scheme utilizing digital signal-processing technique and virtual instrument software, to reduce such noises effectively, taking account of the above-mentioned noise properties. In the scheme, a pick-up coil signal without a magnetic thin film is first sampled and stored in memory as a background noise, then another signal with the thin film is sampled and the stored background noise is reduced. A pick-up coil pair, linear amplifiers, and digital-signal-processing software were optimally designed and installed. A newly designed M-H loop tracer can measure thin soft-magnetic films with a magnetic moment as small as 2.5 × 10-5emu.
    View full abstract
    Download PDF (405K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top