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Magnetics, IEEE Transactions on

Issue 2 • Date Mar. 1997

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Displaying Results 1 - 15 of 15
  • The Seventh Biennial IEEE Conference On Electromagnetic Field Computation (IEEE CEFC '96)

    Publication Year: 1997 , Page(s): 0_1
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    Freely Available from IEEE
  • Analysis of an effective magnetic field in a contact gap of a heavy loaded reed

    Publication Year: 1997 , Page(s): 1037 - 1045
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    Studies of a spatial magnetic field variation within a contact gap of the reed operated under heavy load are reported. The influence of such factors as reed and driving coil parameters as well as contact current value have been investigated. The calculations were carried out using the electronic theory of magnetism and were verified by experiment. On the basis of the results, conclusions about the admissible contact loading of the available standard dry reeds are formulated View full abstract»

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  • 8th Electromagnetic Launch Symposium

    Publication Year: 1997
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    The following topics were dealt with: armatures and launch packages; coilguns; computational techniques; electrothermal and electrothermal chemical launchers; electromagnetic launch applications and materials performance; power conditioning and energy storage; rail launchers; system analysis and integration View full abstract»

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  • A generalized slope model for magnetization transitions

    Publication Year: 1997 , Page(s): 1073 - 1084
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    Based on a multilayer approach, a generalized slope model is outlined for tape media with arbitrary magnetic layer thickness. A systematic study is performed which includes the role of demagnetization, angle dependence of the switching fields, switching field distribution, particle orientation, particle sizes, and geometric effects such as spacing between head and medium. The theoretical results are compared with experimental ones for high-density digital recording and yield excellent agreement between theory and experiment. Fundamentally, this type of lamina model is found to be incapable of treating magnetic screening effects correctly. In the case of metal evaporated (ME) tape with the easy axis tilted out of the film plane, this turns out to limit the usefulness of multilayer models for nonsaturation recording View full abstract»

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  • Architectures for the implementation of a fixed delay tree search detector

    Publication Year: 1997 , Page(s): 1116 - 1124
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    This paper examines the tradeoff between fixed delay tree search (FDTS) detector complexity and performance with various modulation codes. Several architectures suitable for implementing FDTS or achieving performance comparable to FDTS are presented. Recursive forms are derived by decomposing the branch metric computation while breaking down the entire path metric yields nonrecursive forms. The final architecture casts the detection problem into a signal space context in which the observation space is partitioned into decision regions. These structures are presented and evaluated in the context of an analog very large scale integration (VLSI) implementation. Compared to a direct mapping to hardware of the original algorithm, these alternative schemes offer reduced power consumption and/or increased data rate View full abstract»

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  • An effective 3-D finite element scheme for computing electromagnetic field distortions due to defects in eddy-current nondestructive evaluation

    Publication Year: 1997 , Page(s): 1012 - 1020
    Cited by:  Papers (37)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    A new three-dimensional (3-D) finite element scheme for eddy-current nondestructive evaluation (NDE) problems is described that calculates directly the perturbation of the electromagnetic field due to defects in metallic specimens. The computational costs of such problems are usually very high using available finite element schemes, and the new scheme is supposed to lower these costs. The basic concept, the direct calculation of the field distortion due to the flaw, is provided for rather general defects, but the detailed finite element scheme is discussed for zero-conductivity flaws. The source terms of the formulation are determined from the unperturbed field, and the impedance change due to a defect can be calculated as an integral over the flaw. A finite element scheme for solving problems with crack-type defects is also presented as a limiting case of the formulation for zero-conductivity flaws. Solutions of a benchmark problem from the testing electromagnetic analysis methods (TEAM) workshop series (problem number 15/2) and of tube problems with artificial slots are presented and compared to experimental data View full abstract»

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  • Tribology of metal-evaporated tape for high-density magnetic recording

    Publication Year: 1997 , Page(s): 1058 - 1068
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    Magnetic recording density has increased remarkably due to progress in magnetic recording media. Metal-evaporated (ME) tapes may be the ultimate media for the coming era of digital magnetic recording. However, ME tapes are inferior to metal-particulate (MP) tapes in durability against the rubbing of magnetic heads. The use of organic and inorganic protective layers could improve two tradeoff properties such as high output and durability. In this paper, this recent technology is discussed from the viewpoint of tribology View full abstract»

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  • Magnetic force microscopy studies of ultrahigh density magnetic recording on longitudinal and perpendicular media

    Publication Year: 1997 , Page(s): 1052 - 1057
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (212 KB)  

    It has been demonstrated using magnetic force microscopy (MFM) that magnetic recording patterns with linear densities in excess of 230 kfci can be sustained by isotropic longitudinal media with Hc=2500 Oe and perpendicular media with Hc=1800 Oe. It was found that the size of magnetic cluster domains limited the linear recording density sustainable by a longitudinal medium and that the cluster size decreased with increasing medium coercivity. As the bit size approached the minimum cluster size observed in the magnetic background of longitudinal medium, the bits tended to percolate within the track resulting in a complete disappearance of a recorded pattern. In the case of the perpendicular medium, the bit transitions remained sharp at high densities. As the bit size approached minimum cluster domain size, the signal amplitude approached the noise amplitude thus limiting the detectability of the recorded bit pattern View full abstract»

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  • A nonlinearity specification for constructing the servo position error signal

    Publication Year: 1997 , Page(s): 1104 - 1115
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

    A high performance disk file actuator servo requires a position transducer whose response is linear with displacement. Two concerns that detrimentally affect positional linearity are the nonlinear response of the burst detector to burst amplitude and the nonuniform sensitivity of the magnetic read element across its pole faces. Nonuniform field sensitivity is of particular concern with the advent of magneto resistive heads for embedded servo systems, and this paper gives specification for both for good actuator positioning View full abstract»

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  • Rotational hysteresis model for stressed ferromagnetic films

    Publication Year: 1997 , Page(s): 1007 - 1011
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    The effect of an external mechanical stress on the coercive force of Ni is different for bulk and for thin films. The bulk behavior is correctly explained by the Sablik-Jiles model which assumes that wall displacement is the driving mechanism of the magnetization process. In thin films, on the other hand, magnetization rotation might be a relevant mechanism, and this could explain the experimental differences with respect to bulk. In order to verify the correctness of this assumption, we constructed another model which was based on magnetization rotation. This new model is based on the bidimensional Stoner-Wohlfarth model, with additional terms which account for magnetostrictive energy and interactions among grains. Its predictions about coercive force behavior and general cycle shape are compared with experimental data on electroplated and evaporated Ni films with thicknesses from 15 to 200 nm View full abstract»

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  • Power dissipation and magnetic forces on MAGLEV rebars

    Publication Year: 1997 , Page(s): 1021 - 1036
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (984 KB)  

    Concrete guideways for proposed MAGLEV vehicles may be reinforced with electrically conducting and magnetizable steel rebars. Transient magnetic fields due to passing MAGLEV vehicles will then induce transient currents in the rebars leading to power dissipation and temperature rise as well as Lorentz and magnetization forces on the rebars. In order to evaluate if this heating and force on the rebars affects concrete life and performance, analysis is presented for an infinitely long conducting and magnetizable cylinder in imposed uniform axial or transverse magnetic fields. Exact and approximate solutions are presented for sinusoidal steady state and step transient magnetic fields inside and outside the cylinder, the induced current density, the vector potential for transverse magnetic fields, the time average dissipated power in the sinusoidal steady state, and the total energy dissipated for step transients. Forces are approximately calculated for imposed magnetic fields with a weak spatial gradient. The analysis is applied to representative rebar materials View full abstract»

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  • Effect of apparent reversibility on parameter estimation [magnetic recording]

    Publication Year: 1997 , Page(s): 1085 - 1092
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    In materials with large magnetic moments, the interaction field can be sufficiently large so that the Preisach function has a significant contribution outside the fourth quadrant of the Preisach plane. It is shown that such media, even a perfectly aligned medium that has an apparent reversible component, will have nonzero squareness. In this case, one has to distinguish between remanence and the irreversible component of the magnetization. Since measurements cannot distinguish between the two effects, the procedure for the identification of model parameters must model the effects and use their different properties in order to separate them. This paper discusses such an identification procedure View full abstract»

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  • Perpendicular magnetic anisotropy and magnetooptical properties of (Co1-xNix)/Pd multilayers

    Publication Year: 1997 , Page(s): 1049 - 1051
    Cited by:  Papers (1)
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    The magnetic and magnetooptical properties of (Co1-xNi x)/Pd multilayers were systematically investigated. The addition of Ni to the Co layer simultaneously decreases the Curie temperature and Kerr rotation angle, but the decrease of the Curie temperature is larger. By controlling the Ni content it is possible to reduce the Curie temperature. The perpendicular magnetic anisotropy energy also decreases with the addition of Ni, but the change is small. The interfacial anisotropy energy and volume anisotropy energy were calculated and discussed. Adding Ni to the Co layer can yield control of magnetic and magnetooptical properties, while maintaining a large effective perpendicular anisotropy energy View full abstract»

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  • Playback pulse shape and spectra for shielded MR heads

    Publication Year: 1997 , Page(s): 1093 - 1103
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    Simple analytical expressions for the longitudinal surface fields from four types of shielded magnetoresistive (MR) heads, i.e., single element MR heads (both centered and off-center), dual-stripe heads, and “differential” MR heads are derived using superposition and Schwarz-Christoffel transformation. These expressions are utilized to study playback pulse shape and spectra. For the centered shielded MR head as well as the dual stripe shielded MR head, simple accurate formulas for PW50 and D50 are derived. For the dual stripe MR head, the model predicts the position of the first spectral gap null accurately, as well as the voltage spectral shape View full abstract»

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  • Deformed MO loops: appearance of orthogonal components of magnetization

    Publication Year: 1997 , Page(s): 1046 - 1048
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (88 KB)  

    The widely used magnetooptical (MO) loop tracer which measures polarization rotation in terms of light-power levels is not adequate for observing individual magnetization components. Loop tracing with the transverse Kerr effect yielding MO loops is able to determine such single components. We present a differential system for observing the transverse Kerr effect which we have constructed for stable measurements of single magnetization components. Measurements were performed on a soft magnetic thin film 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.

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Meet Our Editors

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