IEEE Transactions on Magnetics

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Displaying Results 1 - 25 of 363
• Magnetic properties of sputtered Bi/sub 3/Fe/sub 5/O/sub 12/

Publication Year: 1989, Page(s):4015 - 4017
Cited by:  Papers (30)
| | PDF (1624 KB)

A series of Bi-substituted yttrium-iron-garnet films were grown including its end members, YIG and BiIG, by an RF-diode sputtering method. The low-temperature magnetization of highly Bi-substituted garnet is much lower than expected from the linear expansion of the lattice. The temperature dependence of the magnetization of these materials is described by a molecular field model in which some of t... View full abstract»

• Comments on "Minimizing power dissipation in a disk file actuator" by E.S. Cooper

Publication Year: 1989, Page(s):4353 - 4354
Cited by:  Papers (4)
| | PDF (146 KB)

The seek control problem that arises in the abovementioned work (see ibid., vol.24, p.2081-91, 1988) is formulated as an optimal control problem with constraints relating directly to specified design limits on input magnitude and power dissipation. The resulting control is optimal for a given peak-to-average power ratio. Power-optimal control and time-optimal control are special cases of this type... View full abstract»

• Magneto-optical properties of highly Al-substituted (Y,Bi)3 (Fe,Al)5O12 sputtered films in short wavelength region

Publication Year: 1989, Page(s):4012 - 4014
| | PDF (536 KB)

The films were prepared on 7059 glass substrates by RF sputtering. The effect of Al substitution on the magnetic and structural properties of Bi-substituted films is discussed. The limit of Bi substitution into the garnet phase was clarified for Al-substituted and nonsubstituted films. The microstructure of the films at the limiting composition and segregation compositions was examined by transmis... View full abstract»

• The synthetical theory and experimental research on the fin-line ferrite isolator

Publication Year: 1989, Page(s):3503 - 3505
Cited by:  Papers (1)
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A synthetical theory has been developed to facilitate the theoretical design and experimental adjustment of a finline ferrite isolator. The device design and performance analysis have been carried out using this theory. Experimental research on the finline ferrite isolator in X-band was simulated. Good agreement between experimental and theoretical results was obtained View full abstract»

• Finite element analysis of 3D multiply connected eddy current problems

Publication Year: 1989, Page(s):4009 - 4011
Cited by:  Papers (3)
| | PDF (252 KB)

Three-dimensional eddy-current problems with multiply connected conductors are formulated in terms of uniquely defined potentials. In the eddy-current-carrying regions, a magnetic vector potential and an electric scalar potential are used. These are coupled to a magnetic scalar potential in most parts of the nonconducting domain. However, in the nonconducting holes' in the conductors, a magnetic ... View full abstract»

• Delayed relaxation in thin-film heads

Publication Year: 1989, Page(s):3212 - 3214
Cited by:  Papers (30)  |  Patents (3)
| | PDF (236 KB)

The delayed relaxation after writing with a Permalloy thin-film head has been studied experimentally. The phenomenon of delayed relaxation is shown to be caused predominantly by stress-induced relaxation of the flux closure domains along the edges of the thin-film-head yoke. It is necessary for this effect that the composition of the Permalloy yields nonzero magnetostriction. The fairly rapid temp... View full abstract»

• Dynamic switching process of sandwich-structured MR elements

Publication Year: 1989, Page(s):4269 - 4271
Cited by:  Papers (21)
| | PDF (208 KB)

The dynamic behavior of sandwich-structured magnetoresistive (MR) memory elements is studied analytically by solving Gilbert's equation together with the one-dimensional micromagnetic torque equation. The typical element is 2 μm×20 μm and consists of two 150-Å thick magnetic layers separated by a 50-Å thick nonmagnetic layer. The easy axis is along the short dimension of th... View full abstract»

• Thermal mark characterization on static magneto-optical media

Publication Year: 1989, Page(s):4045 - 4047
Cited by:  Papers (6)
| | PDF (248 KB)

The authors explore the thermal behavior of multilayer magnetooptic (MO) storage media in thermomagnetic recording. An attempt has been made to develop a variety of useful models for heat transfer in these disks that can be readily interpreted for ongoing media design activity. Experimental techniques have been devised that can probe the spatial and temporal distribution of the thermal field in th... View full abstract»

• Metallurgical conditions for development of adequate magnetic properties in grain oriented silicon iron

Publication Year: 1989, Page(s):3955 - 3957
Cited by:  Papers (2)
| | PDF (240 KB)

The mechanisms underlying the secondary recrystallization process in connection with the production of grain-oriented silicon iron have recently been clarified, throwing light on the microstructural parameters and the relationships which control the development of the final orientation. In particular, the interrelationships among grain growth, texture, and the presence of second-phase particles an... View full abstract»

• Effect of applied stress on the magnetization of amorphous magnetoelastic wires

Publication Year: 1989, Page(s):3617 - 3619
Cited by:  Papers (14)
| | PDF (280 KB)

The magnetization of transversely annealed metallic glass wires (Fe77.5B15Si7.5) was examined as a function of longitudinal stress and torsional strain. The effect of annealing parameters on magnetoelastic coupling of the wires was measured. The wires differ from ribbons of similar composition in several important respects. The domain configuration appears to consi... View full abstract»

Publication Year: 1989, Page(s):3500 - 3502
| | PDF (188 KB)

The authors have explored asymmetrical Y-junction circulator designs for narrowband applications. Exact circulation conditions are found for a general asymmetrical circulator. The circulator design allows the input and transmission ports to be at the same angular distance from the isolation port but not necessarily at 120°C. This feature allows the suppression of high-order mode excitations in... View full abstract»

• Magnetic field near a concrete wall during a lightning stroke

Publication Year: 1989, Page(s):4006 - 4008
Cited by:  Papers (11)
| | PDF (200 KB)

The authors highlight the electromagnetic behavior of a lightning protection system with reference to a concrete wall making use of iron rods as vertical down conductors and horizontal equipotential conductors. The electrical model is obtained by dividing each rod into elementary cells, each represented by an equivalent symmetric π network. During a lightning flash the current flowing through e... View full abstract»

• High coercivity in Sm(FeT)12 type magnets

Publication Year: 1989, Page(s):3309 - 3311
Cited by:  Papers (18)  |  Patents (1)
| | PDF (304 KB)

The magnetic properties and microstructure of melt-spun iron-rich ternary alloys with the ThMn12-type structure are reported. Rapidly quenched samples were prepared with composition SmxFe yTz, where T=Ti, V, Mo, Cu, Al, Si or a mixture of these, and 8<x<20, 76<y<89, and 6<z<12. Some samples has small amounts of B or C added. The results... View full abstract»

• Fully coupled quasi-axisymmetric' magneto-thermal model for skin effects analysis in resistive Tokamak coils

Publication Year: 1989, Page(s):3940 - 3942
Cited by:  Papers (3)
| | PDF (220 KB)

A two-dimensional quasi-axisymmetric time-varying finite-element code that discretizes the magnetic and thermal equations, solving them simultaneously, is presented. Some results obtained in realistic test cases of practical interest are displayed and discussed. The code has been used for the analysis of thermoelectromagnetic stresses in the resistive toroidal field coils of fusion machines under ... View full abstract»

• Differentially DC biased type magnetic field sensor of high sensitivity

Publication Year: 1989, Page(s):3396 - 3398
Cited by:  Papers (4)
| | PDF (248 KB)

The detection principle of a novel magnetic field sensor called the differentially-DC-biased magnetic field sensor which uses a magnetic core is described. The detectable lower limit is extended up to the order of 10-13/√Hz by virtue of the detection principle used, which is analogous to the equilibrium condition of ordinary bridge circuits. By using two cores, a kind of bridge ci... View full abstract»

• Irreversible wall motion in inductive recording heads

Publication Year: 1989, Page(s):3209 - 3211
Cited by:  Papers (15)
| | PDF (276 KB)

The effect of signal-induced irreversible domain wall motion on the isolated transition response of recording heads is investigated. An experimental method is presented allowing differentiation between the effects caused by irreversible wall motion and reversible wall motion. The method, utilizing the injection of a small DC current into the head coil, can also be used to determine whether the irr... View full abstract»

• The model permanent magnet based on iron-dysprosium-carbon

Publication Year: 1989, Page(s):3423 - 3425
Cited by:  Papers (4)
| | PDF (276 KB)

Transformation of Fe17Dy2Cx to Fe 14Dy2C produces Fe-Dy-C alloys with intrinsic coercivities exceeding 1200 kA/m (15 kOe). After the material is crushed to produce -325 mesh (<38 μm) particles, typically 2/3 of the coercivity remains. This improved retention of magnetic hardness is attributed to the nature of the grain boundary region, w... View full abstract»

• Analysis of M-R elements for 108 bit/cm2 arrays

Publication Year: 1989, Page(s):4266 - 4268
Cited by:  Papers (14)  |  Patents (1)
| | PDF (188 KB)

Magnetoresistive memory elements made from 100-Å thick, 65% Ni, 15% Fe, 20% Co layers separated by a 40-Å nonmagnetic layer have been analyzed theoretically. The analysis shows that with lithography capable of a minimum feature size of 0.4 μm and with the ability to deposit nonconducting magnetic keepers, memory arrays with a density of 108 bit/cm2 can be achie... View full abstract»

• Domain formation characteristics during thermomagnetic recording for amorphous TbFe and TbFeCo alloy thin films

Publication Year: 1989, Page(s):4039 - 4041
Cited by:  Papers (3)
| | PDF (376 KB)

The configurational characteristics of thermomagnetically written domains under a static laser irradiation condition were observed by using a polarizing microscope. The shapes of the domains were categorized into three distinctly different types: (1) circular domains with size almost independent of the applied field, (2) domains growing in size and assuming smoother boundaries with increasing appl... View full abstract»

• Grain structure and magnetism of nanocrystalline ferromagnets

Publication Year: 1989, Page(s):3327 - 3329
Cited by:  Papers (890)  |  Patents (8)
| | PDF (264 KB)

Amorphous ribbons of composition Fe73.5Cu1Nb 3Si13.5B9 have been annealed above their crystallization temperature, which produces a homogeneous, ultrafine grain structure of αFeSi with typical grain diameters of 10-20 nm. The temperature dependence of saturation magnetization reveals two different magnetic phases which correspond to the ... View full abstract»

• Collision effects in axial HGMS

Publication Year: 1989, Page(s):3800 - 3802
Cited by:  Papers (5)
| | PDF (220 KB)

A theoretical study is presented of the effect of particle-particle interactions during separation on the performance of continuous, axial, high-gradient magnetic separators. In the separation of a two-particle system, the magnetic particles are swept across the separation zone and collected in a different outlet from that of the nonmagnetic tails. The degree to which they carry with them a certai... View full abstract»

• Direct observation of the dynamic magnetic action in metal-in-gap recording heads

Publication Year: 1989, Page(s):3701 - 3703
Cited by:  Papers (13)
| | PDF (488 KB)

The behavior of the dynamic magnetic switching of metal-in-gap recording heads, observed directly through the use of the magnetooptic Kerr effect, shows significant magnetic action in the vicinity of poorly formed interfaces between Sendust and ferrite. A series of MnZn ferrite heads with increasingly better interfaces between the ferrite and Sendust is examined, and results from magnetooptic meas... View full abstract»

• Semi-hard magnetism of iron nitride films prepared by double ion beam sputtering

Publication Year: 1989, Page(s):3893 - 3895
Cited by:  Papers (2)  |  Patents (3)
| | PDF (220 KB)

The semihard magnetic properties and crystal structure of iron nitride films prepared by double ion beam sputtering have been investigated. The films consisted of Fe layers and FexN layers bombarded by nitrogen ions during deposition. The films were annealed at 300°C for 3 h after deposition. When the thickness ratio of Fe layers to FexN was adjusted to a value below 10 f... View full abstract»

• Effect of the variation in Sm/Cu/Zr content on phase stability of an Sm(Co,Fe,Cu,Zr)7.4 permanent magnet alloy

Publication Year: 1989, Page(s):3782 - 3784
Cited by:  Papers (8)
| | PDF (492 KB)

The effect of composition variation on the phase stability of an Sm(Co,Fe,Cu,Zr)7.4 system was studied to provide information on interpreting phase changes after partitioning of composition in the heat treatment of this alloy. Three quasi-binary phase diagrams were obtained by X-ray diffractometry, differential thermal analysis, scanning electron microscopy, and energy dispersive X-ray ... View full abstract»

• Boundary element analysis of electromagnetic confinement applications

Publication Year: 1989, Page(s):3599 - 3601
Cited by:  Papers (2)
| | PDF (276 KB)

A boundary integral equation (BIE) formulation is derived to represent a mathematical model for a molten metal in a two-ton crucible induction furnace with an induction coil shielded by a nonconducting magnetic yoke. In this formulation, the impedance boundary condition relation is applied in the molten metal region and a special BIE formulation is derived for the yoke region. The strong singulari... View full abstract»

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