By Topic

Magnetics, IEEE Transactions on

Issue 2  Part 1 • Date Feb. 2009

 This issue contains several parts.Go to:  Part 2 

Filter Results

Displaying Results 1 - 23 of 23
  • [Front cover]

    Publication Year: 2009 , Page(s): C1
    Save to Project icon | Request Permissions | PDF file iconPDF (209 KB)  
    Freely Available from IEEE
  • IEEE Transactions on Magnetics publication information

    Publication Year: 2009 , Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (38 KB)  
    Freely Available from IEEE
  • Table of contents

    Publication Year: 2009 , Page(s): 653 - 654
    Save to Project icon | Request Permissions | PDF file iconPDF (61 KB)  
    Freely Available from IEEE
  • International Conference on Microwave Magnetics ICMM 2008

    Publication Year: 2009 , Page(s): 655
    Save to Project icon | Request Permissions | PDF file iconPDF (215 KB) |  | HTML iconHTML  
    Freely Available from IEEE
  • Wideband Microwave Filters Using Ferromagnetic Resonance Tuning in Flip-Chip YIG-GaAs Layer Structures

    Publication Year: 2009 , Page(s): 656 - 660
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB) |  | HTML iconHTML  

    In this paper the most recent advances on ferromagnetic resonance (FMR)-based wideband microwave band-stop and band-pass filters using flip-chip yttrium iron garnet (YIG)/gadolinium gallium garnet (GGG)- gallium arsenide (GaAs) layer structures are reported. Specifically, simultaneous enhancement in tunable bandwidths and peak absorption levels by utilizing the meander microstrip line with step-impedance low-pass filter design together with inhomogeneous magnetic field has been accomplished. For example, an ferromagnetic resonance absorption frequency tuning range of 5 to 21 GHz, an absorption level of -35.5 dB and a corresponding 3 dB absorption bandwidth as large as 1.70 GHz, centered at 20.3 GHz, have been accomplished with the band-stop filter. For the band-pass filter large tuning ranges for the center frequency (5.90-17.80 GHz), the pass-band bandwidth (1.27-2.08 GHz) as well as the two guarding stop-bandwidths (0.45-1.70 GHz), and an out-of-band rejection of -33.5 dB were demonstrated. A good agreement between the simulation and experimental results has been achieved. Finally, some desirable measurement data on the microwave power capability and the magnetic tuning speed of the filters has also been obtained. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Frequencies of Radially Symmetric Excitations in Vortex State Disks

    Publication Year: 2009 , Page(s): 661 - 662
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (74 KB) |  | HTML iconHTML  

    Submicron ferromagnetic disks with a vortex ground state exhibit interesting and potentially useful dynamic properties arising from excitations on the ground state. In particular, a magnetic pulse applied perpendicular to the vortex plane will excite radially symmetric modes. Previous calculations of the frequencies of these modes based on the linearized Landau-Lifschitz equation and the magnetostatic Green's function give eigenfrequencies proportional to the square root of the aspect ratio radic(L/R), where L is the disk thickness and R is the disk radius. However, experimental frequency data show significant deviation from the square root dependence. An improved calculation of the frequency is done through a collective variable approach by exploiting the high symmetry of these modes. In the linear approximation, this approach gives the main contribution to the frequency proportional to radic((L/R)ln(R/L)), which is closer to the observed aspect ratio dependence. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multi-Resonance Mechanism Study for Nanocrystalline Iron/Paraffin Composites Based on Exchange Energy and Bounds in Gigahertz

    Publication Year: 2009 , Page(s): 663 - 665
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB) |  | HTML iconHTML  

    Multi-resonance phenomenon of nanocrystalline iron/paraffin composites is studied based on the general mechanism for each component. Associated with bound relation between the dynamic magnetization and static physical parameters, the relationship between the microwave energy loss and the nature of material is established. It is found that the microwave performance of composites is determined by the competition between natural resonance and exchange resonance, which can be controlled by material's microstructure and geometry features. With this approach, the design of multi-resonance is accessible. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Realization of Far From Equilibrium Cation Distributions in Ferrites

    Publication Year: 2009 , Page(s): 666 - 669
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB) |  | HTML iconHTML  

    The deposition and characterization of high quality ferrite thin films by the alternating target laser ablation deposition (ATLAD) technique is discussed with the emphasis on the unique magnetic properties induced in these materials by stabilizing far from equilibrium cation distributions. Two spinel systems and three hexagonal ferrite systems are studied. In the case of manganese spinel ferrite a large in-plane uniaxial anisotropy field ( > 5 kOe) is induced in ATLAD deposited films. In the case of copper spinel ferrite a 65% enhancement in the saturation magnetization is observed over the bulk value. In the case of manganese substituted barium ferrite a 12-22% enhancement in low temperature saturation magnetization and 40-60 K increase in the Neel temperature is observed. The unique magnetic properties of the films are correlated with the cation distributions stabilized by the application of the ATLAD technique as determined by the extended X-ray absorption fine structure (EXAFS) analysis. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High-Frequency Properties and Attenuation Characteristics of WBa Hexaferrite Composites With Doping of Various Oxides

    Publication Year: 2009 , Page(s): 670 - 677
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (587 KB) |  | HTML iconHTML  

    Doping of various oxides can greatly modify the high-frequency magnetic and dielectric properties and, therefore, significantly influence the impedance matching and bandwidth characteristics of BaCoZnFe16O27 ferrite/epoxy composites. The experiments show that composites doped with V 2O 5 and IrO 2+V 2O 5 are potential candidates for use as EM attenuation materials with low reflectivity and broad bandwidth at S, C, and X microwave bands. The frequency bands for reflectivity |R| les -10 dB cover 3.6 - 13.7 GHz and 3.0 - 11.6 GHz at the thickness of 0.3 and 0.35 cm, and the relative bandwidth WR = 3.8 and 3.9 is achieved, respectively, for composites doped with V2O5 and IrO2+V 2O 5. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modeling the Electromagnetic Behavior of Nanocrystalline Soft Materials

    Publication Year: 2009 , Page(s): 678 - 686
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (553 KB) |  | HTML iconHTML  

    A model that describes the magnetic behavior of nanocrystalline ring cores is useful for simulations of electronic circuits that contain inductors or transformers using these cores. A general but computationally demanding model combines a macroscopic model of the ribbon with a dynamic Preisach hysteresis model. In this paper, we present two models that-taking into account the principle of loss separation-make it possible to avoid the use of the CPU time consuming dynamic Preisach model. Both models compute the waveform of the magnetic flux density for an arbitrary waveform of the magnetic field, or vice versa. The first model uses a macroscopic model based on the plane wave theory and the classical rate-independent Preisach formalism. The macroscopic model operates in the frequency domain and applies the harmonic balance principle. Because of nonlinearity, the model is solved iteratively by a Newton-Raphson scheme. The second model starts from a single evaluation of the classical Preisach model. Additionally, it uses a lookup table that is a function of the flux density and its time derivative to evaluate the classical and excess field to be added. The models are validated by measurements between 2 and 100 kHz on Vitroperm nanocrystalline ring cores. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Three-Dimensional Polycrystal Magnetic Field Analysis of Thin Steel

    Publication Year: 2009 , Page(s): 687 - 693
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1167 KB) |  | HTML iconHTML  

    The 3-D polycrystal magnetic field analysis method by means of coordinate transformation is proposed. The local coordinates are fixed in each crystal grain and the global coordinates are defined in the polycrystal steel. Though it is assumed that each crystal grain has the same magnetized characteristics as those of a single crystal grain, the crystal grain shape and its orientations of alpha, beta, and gamma angles are taken into account. When the proposed model is applied to the real grain oriented (GO) steel with 56 crystal grains in 80-mm × 80-mm, and with 0.35-mm thickness, the calculation results are compared with the grain orientations measured by X-ray diffraction. The GO steel has a higher degree of (110)[001] texture with about 3% silicon. The calculated results of higher magnetic flux density part and lower magnetic flux density part in the real GO steel are explained by the alpha angle distribution. The calculated inclination angle distribution and the measured alpha angle distribution seem to be in good agreement. The calculated normal component of the magnetic flux density reflects the beta angle distribution of the real GO steel. It is concluded that the proposed 3-D polycrystal magnetic field analysis is appropriate. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Permeance of Fringing Flux

    Publication Year: 2009 , Page(s): 694 - 700
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (959 KB) |  | HTML iconHTML  

    Field modeling becomes simpler if strong field nonuniformities are solved theoretically. The early obtained formulas for 2-D ldquocornerrdquo and ldquoconstrictionrdquo permeances pertain to right angle configurations. In this paper, using a conformal mapping, the field in the vicinity of arbitrary angle vertex is studied and the fringing permeance determined. The results are applied to permeance evaluation of lunate cross section grooves from the rotors of certain types of reluctance motors. Closed-form expressions are obtained, in good agreement with finite element analysis. Combined with the finite element method, obtained results offer the possibility to make simpler and more accurate analytical calculations of motors and other magnetic devices and to better evaluate magnetic forces that act on them. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Enhanced Nonlinear Algorithm for the Transient Analysis of Magnetic Field and Electric Circuit Coupled Problems

    Publication Year: 2009 , Page(s): 701 - 706
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (370 KB) |  | HTML iconHTML  

    The time stepping finite element method based on the backward Euler's method has been widely used to simulate transient electromagnetic fields. Because of the numerical error of nonlinear iterations, the solutions of the derivative quantities may have very big noisy spikes. We present a modified formulation that reduces significantly the numerical error of the derivative quantities in transient finite element analysis of magnetic field computation. We also present an example that simulates the operation of an induction motor and demonstrates that the new method can successfully remove the spikes in the calculated waveforms of back electromotive force and eddy-current loss. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Coupling Circuit Systems and Finite Element Models: A 2-D Time-Harmonic Modified Nodal Analysis Framework

    Publication Year: 2009 , Page(s): 707 - 715
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (958 KB) |  | HTML iconHTML  

    A new, systematic way of coupling low-frequency finite-element (FE) models with circuit systems is proposed using a modified nodal analysis framework. Solid and filamentary conductors can be equally treated as magnetic vector potential-controlled voltage sources. Their matrix contributions to the coupled system are basically the same, leading to a natural way of adding conductors to arbitrary circuit topologies. Algebraic equations of the same type describe the coupling between FE and circuit models, for both massive and filamentary conductors. Any class of independent and dependent source can be considered as well as resistances, inductances, capacitances, transformers, auto-transformers and magnetically-coupled branches. The resulting matrix for the coupled problem is symmetric if the circuit configuration does not contain voltage- or current-controlled sources. The methodology is developed for the general nonlinear time-harmonic problem, but it can be extended to the transient case. An induction motor test case is employed to show the power of the new coupling approach. Comparison of the results against a well-known, validated commercial software (Flux2D) shows that the code developed in this work performs efficiently. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comparison of Models for Estimating Magnetic Core Losses in Electrical Machines Using the Finite-Element Method

    Publication Year: 2009 , Page(s): 716 - 725
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (676 KB) |  | HTML iconHTML  

    This paper focuses on the modeling and prediction of core losses in nonoriented magnetic materials of electrical machines. The aim is to investigate the accuracy, efficiency, and stability of certain models, including the commonly used and the advanced ones, and to discuss their advantages and disadvantages when they are implemented in the finite-element method (FEM). It is shown in the paper that the traditional technique based on the loss separation theory can efficiently produce reasonable results in specific operation conditions but can, on the other hand, over- or underestimate the core losses in other circumstances. The advanced model based on solving the one-dimensional (1-D) Maxwell equations can give accurate results for the prediction of core losses in a lamination strip, but its accuracy, stability, and computational burden are put under scrutiny when it is applied to the prediction of core losses in an electrical machine. A third technique, referred to as the hybrid model, which captures the advantages of the traditional and advanced techniques and merges them into one, has been found to be the best compromise. The principal aim of the hybrid model is to avoid the numerical procedure of the 1-D Maxwell equations while maintaining relatively accurate predictions with a reasonable computational burden. A comparative investigation has been conducted for the three core-loss models that have been incorporated into the 2-D FEM analysis of a 37-kW induction motor on which experiments were carried out for comparisons. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Ferrimagnetic Inductor Design Using Population-Based Design Algorithms

    Publication Year: 2009 , Page(s): 726 - 734
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (774 KB) |  | HTML iconHTML  

    In this paper, we set forth a procedure to perform detailed inductor designs using population-based optimization methods. We chose inductor designs on the basis of design inputs, i.e., the inductor geometry and core material. The method incorporates recent research in magnetic materials characterization, advanced inductor modeling, and hysteresis loss modeling. We present several case studies for both single- and multi-objective optimizations. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Novel Winding and Core Design for Maximum Reduction of Harmonic Magnetomotive Force in AC Motors

    Publication Year: 2009 , Page(s): 735 - 746
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1583 KB) |  | HTML iconHTML  

    The familiar method for reducing the space harmonic content of the magnetomotive force (MMF) produced by a distributed polyphase ac winding is by chording, although by itself this can eliminate only one of the major low-order harmonics. Other techniques are available that can further reduce the harmonic content, although these all require a more complex winding arrangement. This paper presents a novel approach by which the winding harmonics can be even further reduced. In addition to altering the winding layout, the method employs an unconventional slotting pattern. The layout and the slot layout are both optimized to produce an MMF distribution that contains fewer harmonics than any conventional arrangement, while still preserving a high fundamental winding factor. The paper presents an example of the new technique in the design of a squirrel cage induction motor, and compares important features of the design with those of a standard machine. It summarizes the advantages and disadvantages of the novel approach. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analytical Model of Slotted Air-Gap Surface Mounted Permanent-Magnet Synchronous Motor With Magnet Bars Magnetized in the Shifting Direction

    Publication Year: 2009 , Page(s): 747 - 758
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2111 KB) |  | HTML iconHTML  

    An analytical model is presented, which uses two-dimensional field theory in polar coordinates to determine the flux density distribution, cogging torque, back EMF and electromagnetic torque in the slotted air gap of permanent-magnet motors with surface mounted magnet bars which are magnetized in shifting direction. The magnet arc to pole pitch ratio in the motor is not necessarily equal to unity like in the case of Halbach array magnetization. The effect of stator slots is introduced by modulating the magnetic field distribution in the slotless stator by the complex relative air-gap permeance. With this complex permeance, the radial and tangential components of flux density are calculated. In the analytical and numerical study a finite number of magnet bars, which is considered sufficient to get a sinusoidal magnetization, is used. The influence of the number of magnet bars on magnetization is also investigated. The accuracy of the developed model is verified by comparing its results with those obtained from experimental measurement and previously validated linear and nonlinear numerical finite element code. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Characteristic Performance Analysis of Squirrel Cage Induction Motor With Broken Bars

    Publication Year: 2009 , Page(s): 759 - 766
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1796 KB) |  | HTML iconHTML  

    This paper presents the results of an investigation of the effects of broken squirrel-cage bars. In the investigation, a comprehensive time-stepping coupled finite element approach was fully used to compute stator current waveforms, torque, magnetic flux density waveform, the rotor bar currents, and end-ring currents for three cases: no broken bars, one broken bar, and two adjacent broken bars. The iron core loss distributions in the stator are computed, and the harmonic component of air gap flux density is analyzed. This paper also gives the computed rotor parameters and the vector diagram of the rotor current in cages with and without broken bars. From these data, the faulty signatures are extracted. Experimental results derived from a two-pole 1.1 kW induction motor confirm the validity of the proposed method. Furthermore, this method, which could help to develop diagnostics of broken bars and performance evaluation of induction motor, has great potential in future applications. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Equivalent Magnetization Current Method Applied to the Design of Gradient Coils for Magnetic Resonance Imaging

    Publication Year: 2009 , Page(s): 767 - 775
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1204 KB) |  | HTML iconHTML  

    A new method is described for the design of gradient coils for magnetic resonance imaging systems. The method is based on the known equivalence between a magnetized volume surrounded by a conducting surface and its equivalent representation by a surface current density. The curl of a vertical magnetization vector of a magnetized thin volume is equivalent to a surface current density whose stream line defines a coil current pattern. This concept is applied to the design of gradient coils of arbitrary shape. The thin magnetized volume is discretized in small triangular elements. By calculating the contribution of each magnetized block at target points a field source matrix is obtained. The equivalent magnetization current concept is applied to obtain the equivalent coil impedance, force and torques. A quadratic programming optimization algorithm is used to obtain the stream-magnetization-thickness function value at each node such that coils of optimal performance are obtained. This method can be used for gradient coils wound on arbitrary surface shapes and can be applied to hybrid current/iron solutions. A variety of examples are shown to demonstrate the versatility of the method. A novel partially shielded 3-D biplanar gradient coil for open MRI magnets is presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Power and Area Optimization for Run-Time Reconfiguration System On Programmable Chip Based on Magnetic Random Access Memory

    Publication Year: 2009 , Page(s): 776 - 780
    Cited by:  Papers (9)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (572 KB) |  | HTML iconHTML  

    In recent years, magnetic random access memory (MRAM) based run-time system on programmable chip (SOPC) has been proposed as a solution to the critical drawbacks of current field programmable gate arrays (FPGAs), such as long (re)boot latency, high standby power, and limits for run time reconfiguration. However, the integration of MRAM in FPGA circuits brings its own problems, including large die area and high dynamic power for the switching circuit. In this paper, we present some solutions to overcome the power and area constraints and thereby improve the performance of MRAM based SOPC. We have done simulations and calculations based on the STMicroelectronics 90 nm design kit and a complete magnetic tunnel junction model. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • IEEE Magnetics Society Information

    Publication Year: 2009 , Page(s): C3
    Save to Project icon | Request Permissions | PDF file iconPDF (31 KB)  
    Freely Available from IEEE
  • IEEE Transactions on Magnetics institutional listings

    Publication Year: 2009 , Page(s): C4
    Save to Project icon | Request Permissions | PDF file iconPDF (271 KB)  
    Freely Available from IEEE

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