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Magnetics, IEEE Transactions on

Issue 1 • Date January 1978

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Displaying Results 1 - 10 of 10
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • Replicate/transfer bubble switch

    Page(s): 1 - 4
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    A replicate/transfer switch compatible with the gap tolerant structure has been developed. The switch characteristics are superior to that of the existing switches both at the the 8-μm and 16-μm periods. The switch offers the advantages of good bias and phase margins, ease of fabrication, and reduced drive field requirements. In the 8-μm version the device requires a substantially lower drive field than the pickax design by virtue of reduced bubble-bubble interaction in the minor loops. View full abstract»

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  • Effect of various stress-relief annealing treatments on permeability and aging of grain-oriented electrical steel strips

    Page(s): 4 - 8
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    A series of controlled experiments was performed to investigate the effect of various stress-relief annealing treatments on magnetic permeability and tendency to aging of grain-oriented electrical steel strips M5, 0.30 mm. The best quality is produced by stress-relief annealing in a continuous roller type furnace. However, wound transformer cores have to be stress-relief annealed in a batch type furnace. Stress-relief annealing in batch type furnaces demands an appropriate temperature treatment and a protective atmosphere. Special care should be taken to prevent contamination by carbon. Carbon content in an amount greater than 0.001 percent considerably deteriorates magnetic properties at low inductions and increases the tendency of grain-oriented electrical steel strips to aging. Plastic deformation of electrical steel strips occurring during manufacturing of magnetic circuits should be avoided as much as possible. Magnetic properties impaired by them can never be fully recovered by stress-relief annealing, and they remain deteriorated with the effect being higher for the higher degree of plastic deformation. View full abstract»

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  • Aging of grain-oriented electrical steel strips

    Page(s): 9 - 13
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    A high rate of manufacturing rejects occur from time to time in production lots of instrument current transformers. This has initiated a systematic search for the causes. One cause is the aging of grain-oriented electrical steel strips. Presented are the effects of aging on magnetic ac permeability, over a wide range of inductions from 0.005 T to 1.4 T on laminated and wound cores exposed to temperatures of 150°C and 60°C for up to 10 000 hours. These cores were made from M5 grain-oriented electrical steel strips 0.30 mm thick from various manufacturers. It has been found that the steel manufacturers have generally solved the aging problem of the grain-oriented electrical steel strips, since strips of most manufacturers do not age in the as-supplied condition. However, certain quantities of the grain-oriented electrical steel strips of some steel manufacturers show a considerable tendency to aging. The instrument current transformer manufacturers, therefore, should by proper quality control limit the steel suppliers to those who manufacture a consistent product. Another cause of aging could also be an improper stress relief annealing performed by the instrument current transformer manufacturers. View full abstract»

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  • Effect of forsterite coatings on the domain structure of grain-oriented 3-percent Si-Fe

    Page(s): 14 - 17
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    Domain structures were observed in polycrystalline, high permeability grain oriented 3-percent Si-Fe before and after formation of a forsterite coating. A 200 kV scanning electron microscope was used for domain observations. Significant alterations in the supplementary (flux closure) domain structure and a substantial refinement in the 180° domain wall spacing were produced by the forsterite coaling. Increased pinning of 180° walls by inclusions was observed after fotsterite coating. These inclusions are most likely parlicles of forsterite lying just below the sheet surface. The effects of forsterite coatings on domain structure are believed to be caused by changes in surface roughness occurring after forsterite coating. Possible effects of these variations in domain structure on losses are discussed. View full abstract»

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  • A vibrating coil magnetometer for quality control in relay manufacturing

    Page(s): 17 - 21
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    Where relay performance is shown to depend on the coercive force of the material used in the cote, accurate but convenient measurement of this material property forms part of production quality control. A magnetometer for this purpose is described and some results presented to show the necessity for such measurements. View full abstract»

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  • Properties of high-gradient magnetogravimetric systems--I. Single rods and gratings with oval and circular cross sections

    Page(s): 21 - 27
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    The properties of two-dimensional rod systems are examined, use being made of the complex potential in conjunction with the conformal-transformation technique. The concept of prescribed trajectories whereby stronger, effective, levitational forces can be obtained is introduced. It is shown that the high-gradient magnetogravimetric-separation system is amenable to scale-up since sufficient levitational force, in terms of the equivalent specific gravity, is generated. Examples of gratings with circular and different oval cross sections, which are subject to the magnetizing field in two alternative directions, are discussed. View full abstract»

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  • YIG rod ferrite limiter with extended dynamic range

    Page(s): 28 - 30
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    Analytical and experimental results obtained on aC-band ferrite limiter which utilizes a YIG rod inserted down the center of a coupled dielectric resonator bandpass structure are described. This device is aimed at providing receiver protection for communication systems operating in a dense, high signal power environment. By utilizing a long thin single-crystal YIG rod instead of YIG spheres, the dynamic range has been extended from 20 dB to 35 dB. The threshold power varies from 5 dBm at 4.4 GHz to 15 dBm at 5 GHz with an insertion loss of less than 1 dB. View full abstract»

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  • [Back cover]

    Page(s): 0
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    Freely Available from IEEE
  • Magnetooptic color effects in bismuth garnet domains

    Page(s): 31 - 32
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    Domains in magnetic materials having a dispersive Faraday coefficient appear in various colors when viewed by the Faraday effect. If the polarizer and analyzer are slightly uncrossed, domains appear in four colors, three spectral colors and black, depending on the local normal component of magnetization. A theory is presented for this effect. Experimental values of color observed in bismuth substituted garnet films as a function of normal applied field agree with the theory. This effect permits one to discern the average normal component of magnetization at a spot on a micrograph from the color at, that location. Besides the usual bubbles and stripes, unusual domains such as bubble spikes and diamonds and stripe arrays in which the normal component of the magnetization does not change sign are reported. 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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Editor-in-Chief
Pavel Kabos
National Institute of Standards and Technology