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IEEE Transactions on Magnetics

Issue 6 • Nov. 1999

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Displaying Results 1 - 20 of 20
  • Author index

    Publication Year: 1999, Page(s):1 - 40
    Cited by:  Papers (1)
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    Freely Available from IEEE
  • Subject index

    Publication Year: 1999, Page(s):40 - 140
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    Freely Available from IEEE
  • Demagnetization factors of ringcores

    Publication Year: 1999, Page(s):4440 - 4444
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (116 KB)

    The expression for the demagnetization of ringcores has evolved from the equation for the magnetic field inside simple-shaped objects whose magnetization is uniform. A modified expression that allows for the angular distribution of the magnetic field in the ringcore is developed from calculations for a infinite length tube. The modified expression is shown to provide a good fit to measured data. T... View full abstract»

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  • Thermal effect limits in ultrahigh-density magnetic recording

    Publication Year: 1999, Page(s):4423 - 4439
    Cited by:  Papers (770)  |  Patents (34)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (572 KB)

    In current longitudinal magnetic recording media, high areal density and low noise are achieved by statistical averaging over several hundred weakly coupled ferromagnetic grains per bit cell. Continued scaling to smaller bit and grain sizes, however, may prompt spontaneous magnetization reversal processes when the stored energy per particle starts competing with thermal energy, thereby limiting th... View full abstract»

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  • Measurement and interpretation of magnetic time effects in recording media

    Publication Year: 1999, Page(s):4414 - 4422
    Cited by:  Papers (65)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (140 KB)

    Magnetic time effects are highly relevant to magnetic information storage because of the large difference (up to 16 or 17 orders of magnitude) between the time scales of the recording process and the required storage stability. Magnetic time effects become more pronounced as the volume of the switching unit becomes smaller, and thus become of more practical importance as the microstructure of reco... View full abstract»

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  • Fluctuation aftereffect in magnetic materials

    Publication Year: 1999, Page(s):4407 - 4413
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (152 KB)

    Time dependence of magnetization under constant field conditions is exhibited by all materials subject to hysteresis. The phenomenon is a consequence of thermal activation of irreversible magnetization effects from metastable to stable states. Experimental observations of time dependence may be accounted for by considering distributions of the energy required for activation of the metastable state... View full abstract»

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  • Analytical calculation of the switched reluctance motor's unaligned inductance

    Publication Year: 1999, Page(s):4473 - 4481
    Cited by:  Papers (59)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    This paper develops an analytical model for the unaligned inductance of the switched reluctance motor. The analytical model is useful as long as the machine's stator and rotor poles do not overlap and its iron does not saturate. Iron saturation is almost never experienced when the rotor is in the unaligned position for practical winding currents. This paper expands on results presented previously ... View full abstract»

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  • Magnetoresistive read/write channel models

    Publication Year: 1999, Page(s):4528 - 4531
    Cited by:  Papers (11)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (72 KB)

    We studied the magnetic read/write channel with a magnetoresistive (MR) read head at a normalized channel density range of 2.5-3.0, observing and modeling partial erasure and nonlinear transition shift. The asymmetry of the MR head had a significant effect on the channel. We applied the transition-width-reduction model, the partial-erasure-plus-transition-shift model, and the Volterra model to the... View full abstract»

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  • Perfectly matched anisotropic layer for the numerical analysis of unbounded eddy-current problems

    Publication Year: 1999, Page(s):4452 - 4458
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (172 KB)

    An extension of the perfectly matched layer (PML) technique in quasi-static fields is developed. The new low frequency PML is based on a fictitious medium with diagonal tensor anisotropy. On the basis of a theoretical investigation, the material properties of the anisotropic layer are specified, so that it will be reflectionless for an arbitrary eddy-current field that may exist in free space. Fur... View full abstract»

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  • Optimization method for permanent-magnet structures

    Publication Year: 1999, Page(s):4465 - 4472
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (180 KB)

    A nonlinear optimization method useful for designing permanent-magnet structures is presented. The method determines an optimal arrangement of magnetic material so that the magnitude of the remanence is spatially uniform and the field generated by the magnet satisfies a set of prescribed linear constraints. In addition, it is shown how to impose auxiliary conditions on the remanence in order to si... View full abstract»

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  • High-rate coding system for magnetic recording

    Publication Year: 1999, Page(s):4522 - 4527
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (124 KB)

    A coding system for magnetic recording channels combining a high-rate error detection code with a list Viterbi algorithm (LVA) is proposed. This coding system can provide a coding gain of up to 2-3 dB for a modified extended extended partial response class IV (EEPR4) channel. A pipelined implementation of the LVA is presented, and an accurate estimation technique for the LVA performance is develop... View full abstract»

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  • Series solution of an eddy-current problem for a sphere with varying conductivity and permeability profiles

    Publication Year: 1999, Page(s):4445 - 4451
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (204 KB)

    Two-parameter families of analytical solutions are found for a single-turn coil symmetrically located above a two-layer sphere. Several cases are considered where the conductivity and relative magnetic permeability of the outer spherical layer are functions of the distance ρ from the sphere's center. The change in impedance of the coil is obtained in terms of a series containing Bessel functio... View full abstract»

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  • Actuator gains for a toothless permanent-magnet self-bearing motor

    Publication Year: 1999, Page(s):4482 - 4489
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (388 KB)

    Permanent-magnet self-bearing motors provide independent bearing and motoring functionality in a single magnetic actuator. Typically, self-bearing motor designs use toothed stators to provide minimum reluctance flux paths that create the magnetic bearing forces necessary to support the rotor. These toothed designs can have significant cogging torque, rendering them ineffective for smooth torque ap... View full abstract»

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  • Magnetoresistive read nonlinearity correction by a frequency-domain approach

    Publication Year: 1999, Page(s):4532 - 4534
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (48 KB)

    The readback process of a magnetoresistive (MR) head is intrinsically nonlinear. To correct the nonlinearity, a new technique based on a frequency-domain measurement is proposed. In this technique, square-wave patterns of certain frequencies are written as probing signals. The harmonics of the readback signals are then measured and used to derive the coefficients of a correction polynomial. Experi... View full abstract»

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  • Uniform treatment of different conductor types in two-dimensional eddy-current problems applied to a fast ferrite tuner

    Publication Year: 1999, Page(s):4459 - 4464
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    This paper deals with the numerical solution of two-dimensional (2-D) eddy-current problems. It shows that the numerical description of current-fed massive conductors is closely related to the numerical description of voltage-fed thin wire coils. With the help of this result, a boundary element method-finite element method code originally designed to deal with thin-wire coils could be applied to t... View full abstract»

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  • Obtaining a frequency-dependent and distributed-effects model of magnetic components from actual measurements

    Publication Year: 1999, Page(s):4490 - 4502
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    The behavior of the magnetic components in high frequency switched power supplies depends significantly on the working frequency because of distributed magnetic and electrical field effects. Measurement equipment such as an impedance analyzer usually offers simple equivalent models that allow characterization of the frequency behavior of some magnetic components. However, it is useful to have a pr... View full abstract»

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  • New frequency-domain technique for joint measurement of nonlinear transition shift and partial erasure

    Publication Year: 1999, Page(s):4535 - 4537
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (40 KB)

    Nonlinear transition shift (NLTS) and partial erasure have been measured independently by traditional time- or frequency-domain techniques without considering the interference between the two. In some cases, such interference can severely distort the measurement results. To solve this problem, a new frequency-domain technique is proposed that measures NLTS and partial erasure jointly. At each give... View full abstract»

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  • Synthesis study of magnetic torque sensors

    Publication Year: 1999, Page(s):4503 - 4510
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (136 KB)

    There exist numerous solutions to measure the torque applied to a structure or a shaft, and we first present the available devices. They fall into two groups; some measure the torsion angle resulting from the applied torque, others use the shaft material property changes due to the induced stresses, We then present our contribution in this area: a synthesis study of torque sensors with variable-re... View full abstract»

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  • Noise-predictive maximum-likelihood method combined with infinite impulse response equalization

    Publication Year: 1999, Page(s):4538 - 4543
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    An infinite impulse response (IIR) can closely approximate the high density magnetic recording channel response with only a single pole and a small number of zeros. As a consequence, a near-optimal performance can be achieved with the Viterbi algorithm (VA) incorporating a single-tap noise predictor. The number of states in the VA trellis is determined by the number of zeros used in the IIR modeli... View full abstract»

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  • Nonlinear ferromagnetic resonance and foldover in yttrium iron garnet thin films-inadequacy of the classical model

    Publication Year: 1999, Page(s):4511 - 4521
    Cited by:  Papers (28)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (172 KB)

    A thin-film resonator structure has been used for quantitative measurements of ferromagnetic resonance foldover and the associated bistable power response for yttrium iron garnet (YIG) thin films. The resonator consisted of a 1-mm by 1-mm-square, 4.9 μm-thick epitaxial YIG film on top of a 50 μm-wide, 3-mm-long microstrip transducer. A static magnetic field of 3200 Oe was applied perpendicul... View full abstract»

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Aims & Scope

IEEE Transactions on Magnetics publishes research in science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Pavel Kabos
National Institute of Standards and Technology