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Magnetics, IEEE Transactions on

Issue 3 • Date May 1975

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Displaying Results 1 - 13 of 13
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • A contribution to the investigation of fine-particle solid solutions between cubic iron sesquioxide γFe2O3and cobalt ferrite CoFe2O4

    Page(s): 894 - 900
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    The authors give the chemical, morphological, crystallographic, and magnetic properties of solid solutions between cubic iron sesquioxide γFe2O3and cobalt ferrite CoFe2O4obtained as fine particles by a new preparation method. This method gives the whole range of compositions and allows shifting of the magnetic and morphological features in a direction suitable for magnetic recording applications. View full abstract»

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  • Influence of annealing temperature and time on hysteresis parameters and microstructure of an Fe/Co/V alloy

    Page(s): 901 - 907
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    The variations in coercivity, remanence, and microstructure for2frac{1}{2}hour aging anneals between 300°C and 1000°C on an Fe/Co/3% V alloy have been determined. Additionally, the effects of varying aging times for temperatures between 885°C and 925°C have been analyzed. Hysteresis parameters and optical microstructures were characterized on wire samples which had been either cold worked by stamping or remained undeformed prior to the aging anneals. Results show that the alloy exhibits maximum magnetic hardness in its initial cold worked or undeformed conditions. Aging anneals produce a general decrease in magnetic properties with increasing temperatures to 700°C. However, the deformed material exhibits a secondary maximum for aging temperatures between 590°C and 610°C. For anneals above 800°C magnetic parameters again increase as a two-phased, duplex BCC (α1+ α2) structure is developed. By varying the aging time for anneals that produce this duplex structure, a level of coercivity comparable to that achieved for a 600°C anneal was attainable. However, a comparable level of remanence and, thus, a similar squareness ratio, could not be produced with the duplex structures developed by aging near 900°C. View full abstract»

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  • Annotated literature survey of microwave ferrite materials and devices

    Page(s): 907 - 926
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    An annotated literature survey covering major development in the area of microwave ferrite materials and devices for the period 1968-1974 is presented. View full abstract»

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  • Simple model describes error-causing defects in recording disks

    Page(s): 926 - 928
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    Defects causing extra-bit errors on a magnetic storage disk can be represented by a simple model. An experiment supporting the validity of the model is described. View full abstract»

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  • On the convergence of iterative solutions of the integral magnetic field equation

    Page(s): 928 - 933
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    The solution of the integral magnetic field equation by numerical iteration is discussed. Using a simple linear example, it is shown rigorously that relaxation techniques are required to obtain convergence. The range of permissible relaxation parameters is examined and that particular value which yields most rapid convergence is determined. An iterative solution to a simple nonlinear problem is shown to converge rapidly if the relaxation parameter is adjusted appropriately at each step in the iteration. For the general case of a saturable media of complex geometric shape, a relaxation matrix method is proposed in order to achieve rapid convergence. View full abstract»

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  • A magnetic recording simulation program having an improved fit to actual hysteresis loops

    Page(s): 934 - 941
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    In recent years a better understanding of the magnetic recording process has resulted from self-consistent iterative calculations of the magnetization transition induced in the recording medium. One important limitation on these calculations has been the difficulty in fitting realistic hysteresis loops into these calculations. It is not practical to include the actual hysteresis loops, so the practice has been to approximate them by various plausible models. However, none of these models fit the actual loops as closely as would be desired. In this paper, we avoid modelling the major loops, but approximate them using spline interpolation. We demonstrate, by comparison with experimental loops, that the actual loops can be approximated much more closely than with an analytic model. A criterion for deriving the minor loops is given, and we demonstrate a generally better fit of the initial minor loops than that obtained from a model. A self-consistent iterative calculation is made using both an analytic model and the spline approximated loops. We find that the choice of loop model noticeably affects the calculated magnetization distribution and that the spline approximated loops lead to a transition width which more closely matches the width estimated from an experimental single readback pulse. In summary, we demonstrate that good simulation of the hysteresis loops can be significant and discuss a simple approximation technique from which an excellent fit to actual loops can be obtained. View full abstract»

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  • Computer-aided design of saturated round magnetics lenses

    Page(s): 942 - 947
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    The problem of lens convergence because of very high voltages used in electron microscopy can be mastered with superconducting lenses, the magnetic circuit of which is partly saturated. The equations of magnetostatics have to be solved directly for the investigation of the properties of such lenses. A network method is used and it is shown how to establish finite-difference equations for the solution of equations referring to saturated magnetic materials. A computing program for symmetrical lenses is described, and the accuracy of the solution is estimated by comparison of the computational results with those measured on an actual lens. View full abstract»

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  • A practical magnetic bubble AND-OR gate

    Page(s): 953 - 954
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    The design and operation of a magnetic bubble AND-OR gate are reported. Operation at 100 kHz in a 25 Oe rotating field with 28.2 μm circuit periodicity was achieved with about 50 percent of the free bubble bias field margins. A transfer pulse is used to divert bubbles from a propagation path which delivers the AND output tO one which delivers the OR output. The transfer is defeated by the presence of a bubble in the appropriate cycle of the OR path. The AND bubble is then delayed by one cycle instead of being transferred. This frastrated transfer strategy was devised to circumvent the restrictive bias field limitations in the operation of previous logic circuits. View full abstract»

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  • Electromagnets with spherical pole tips

    Page(s): 954 - 955
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    A general equation for the axial magnetic field at any point due to a cylindrical pole-piece with a spherical pole tip magnetized uniformly to saturation is derived in terms of the various distances and linear dimensions. In conclusion, brief remarks are made on the general usefulness of the equations. View full abstract»

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  • [Back cover]

    Page(s): 0
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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