# IEEE Magnetics Letters

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Displaying Results 1 - 25 of 27
• ### Front Cover

Publication Year: 2012, Article Sequence Number: 0000101
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• ### IEEE Magnetics Society Information

Publication Year: 2012, Article Sequence Number: 0000201
| PDF (135 KB)
• ### IEEE Magnetics Letters Publication Information

Publication Year: 2012, Article Sequence Number: 0000301
| PDF (112 KB)
• ### Blank page

Publication Year: 2012, Article Sequence Number: 0000401
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Publication Year: 2012, Article Sequence Number: 0000502
| PDF (98 KB)
• ### Exact Analytical Demagnetizing Factors for Long Hollow Cylinders in Transverse Field

Publication Year: 2012, Article Sequence Number: 0500104
Cited by:  Papers (6)
| | PDF (224 KB) | HTML

Analytical expressions are derived for the magnetometric Nm and fluxmetric Nf demagnetizing factors of infinitely long, hollow cylinders with uniform susceptibility in transverse uniform applied field. Whereas Nm depends on both permeability μ and the ratio of the internal and external radii of the cylinder, Nf does not depend on μ. The magnetic induction ... View full abstract»

• ### Forces between a permanent magnet and a soft magnetic plate

Publication Year: 2012, Article Sequence Number: 0500204
Cited by:  Papers (2)
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Forces between a hard/permanent magnet of arbitrary shape and an ideally soft magnetic plate in close proximity are derived analytically from the image method applied to magnetostatics. We found that the contact force, defined as the force required to detach the hard magnet from the plate, coincides with that between two identical touching permanent magnets. Furthermore, if the hard and the soft m... View full abstract»

• ### Waveguide Tubes Coated With Inhomogeneous Lossy Materials for Superior Shielding Above and Below Cutoff Frequency

Publication Year: 2012, Article Sequence Number: 0500304
Cited by:  Papers (2)
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A new approach for enhanced electromagnetic interference shielding of metallic waveguide (WG) tubes coated with inhomogeneous lossy materials is proposed based on numerical simulation. Shielding enhancement is achieved by using stepped variations of complex permittivity and complex permeability coating materials along the WG transverse direction. Such variation in the coating layer provides multip... View full abstract»

• ### Universal Behavior of Biomolecule-Concentration-Dependent Reduction in AC Magnetic Susceptibility of Bioreagents

Publication Year: 2012, Article Sequence Number: 1500104
Cited by:  Papers (10)
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Magnetic nanoparticles biofunctionalized with antibodies are useful for specifically labeling target biomolecules. By measuring magnetic signals after the association between biofunctionalized magnetic nanoparticles and target biomolecules, the concentration of target biomolecules can be quantitatively detected. One of measuring methodologies is so-called immunomagnetic reduction (IMR), in which t... View full abstract»

• ### Low Energy Magnetic Domain Wall Logic in Short, Narrow, Ferromagnetic Wires

Publication Year: 2012, Article Sequence Number: 3000104
Cited by:  Papers (44)  |  Patents (1)
| | PDF (330 KB) | HTML

We present circuit simulation results of an implementation of universal logic that operates at low switching energy. Information is stored in the position of a single domain wall in a thin, short ferromagnetic wire. The gate is switched by current-driven domain wall motion, and information is read out using a magnetic tunnel junction. The inputs and outputs of the device are currents controlled by... View full abstract»

• ### CoFeB Thickness Dependence of Thermal Stability Factor in CoFeB/MgO Perpendicular Magnetic Tunnel Junctions

Publication Year: 2012, Article Sequence Number: 3000204
Cited by:  Papers (41)
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Thermal stability factor Δ of the recording layer was studied in perpendicular anisotropy CoFeB/MgO magnetic tunnel junctions (p-MTJs) with various CoFeB recording layer thicknesses and junction sizes. In all series of p-MTJs with different thicknesses, Δ is virtually independent of the junction sizes of 48-81 nm in diameter. The values of Δ increase linearly as the recording ... View full abstract»

• ### Spin-Transfer Torque Switching Above Ambient Temperature

Publication Year: 2012, Article Sequence Number: 3000304
Cited by:  Papers (3)
| | PDF (364 KB) | HTML

We report the temperature dependences of tunneling magnetoresistance ratio, coercivity, thermal stability, and switching current distribution of magnetic tunnel junctions (MTJs) in the temperature range 25-80°C, the most probable working environment for spin-transfer torque random access memory (STT-RAM). Two distinct temperature dependence of the switching current density are apparent due ... View full abstract»

• ### Appearance of Anisotropic Magnetoresistance and Electric Potential Distribution in Si-Based Multiterminal Devices With Fe Electrodes

Publication Year: 2012, Article Sequence Number: 3000404
Cited by:  Papers (4)
| | PDF (349 KB) | HTML

We have investigated the influence of anisotropic magnetoresistance (AMR) on nonlocal signals in Si-based multiterminal devices with ferromagnetic Fe electrodes. The AMR of the Fe electrodes has a significant influence on nonlocal signals when the in-plane device structure is not optimized. Our conformal mapping calculations show that it is virtually impossible to realize a pure spin current by sp... View full abstract»

• ### Experimental Study of the Variation in Oscillation Characteristics of Point-Contact-Based Spin-Torque Oscillators

Publication Year: 2012, Article Sequence Number: 3000504
Cited by:  Papers (5)
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This paper presents an experimental study of the variation in oscillation characteristics of circular point-contact-based spin-torque oscillators (PC-STOs). We first measured the oscillation behavior of multiple, identically fabricated PC-STOs, then made the same measurements on a PC-STO and rotated the azimuth angle of the bias field $varphi$ View full abstract»

• ### Write error rate slopes of in-plane magnetic tunnel junctions

Publication Year: 2012, Article Sequence Number: 3000604
Cited by:  Papers (5)
| | PDF (325 KB) | HTML

Understanding bit error rates of magnetic tunnel junctions (MTJs) is critical for designing reliable spin-transfer-torque magnetoresistive random access memory. In this letter, we study the write error rate (WER) of two types of in-plane MTJs with the same film stacks except for the free layer and the capping layer. By comparative analysis of these two MTJ splits that show significantly different ... View full abstract»

• ### Microwave-Assisted Magnetic Reversal in Perpendicular Media

Publication Year: 2012, Article Sequence Number: 3500104
Cited by:  Papers (15)
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Microwave-assisted magnetic reversal (MAMR) has not yet been characterized in hard perpendicular media. We investigate MAMR in such media experimentally for monolayer and bilayer magnetic thin films. The coercive field can be reduced by 8% in our geometry. The response occurs over a broad frequency range which is due to the excitation of long-wavelength spin-wave modes which can help drive reversa... View full abstract»

• ### Magnetization Dynamics in Vortex-Imprinted Ni$_{80}$ Fe$_{20}$/Ir$_{20}$Mn$_{80}$ Square Elements

Publication Year: 2012, Article Sequence Number: 3500204
Cited by:  Papers (1)
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The dynamic behavior of the vortex magnetization on micrometer-sized, ferromagnetic/antiferromagnetic (FM/AFM) bilayer exchange-coupled square elements is investigated using time-resolved Kerr effect microscopy and micromagnetic modeling. $10 mu$ m $times 10 mu$ m squ... View full abstract»

• ### Magnetic Frustration in Circular Arrays of Dipoles

Publication Year: 2012, Article Sequence Number: 4000104
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Magnetostatically interacting structures consisting of 1.5 μm diameter rings of radially oriented nanomagnets were investigated using magnetic force microscopy. An even number of nanomagnets, 16 in this case, formed a ground state in which the magnetizations of neighboring nanomagnets were oriented antiparallel. However, an odd number of nanomagnets, 15, led to a frustrated state in which a... View full abstract»

• ### Large Exchange Bias Field in (Pt/Co) $_{bf 3}$/IrMn/Co Trilayers With Ultrathin IrMn Layers

Publication Year: 2012, Article Sequence Number: 4000204
Cited by:  Papers (9)
| | PDF (304 KB) | HTML

The field shift of the hysteresis loop, called exchange bias field, in ferromagnetic/antiferromagnetic (F/AF) Co/IrMn bilayers, or (Pt/Co),,/IrMn structures, appears only above a critical thickness of IrMn, which is related to the IrMn magnetocrystalline anisotropy and to the interfacial coupling between the F and AF layers. In this letter, we show that this critical IrMn thickness can be consider... View full abstract»

• ### Novel Approach to Control Diameter of Self-Rolled Magnetic Microtubes by Anodizing Ti Layer

Publication Year: 2012, Article Sequence Number: 4000304
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Stress engineering in multilayered thin-film patterns is the key to control the diameter of self-rolled magnetic structures. Arrays of magnetic microtubes were fabricated via a deterministic release of rectangular thin-film patterns of Ti(20 nm)/Ni(30 nm)/Au(2 nm) and Ti(20 nm)/GaFe(40 nm)/Au(15 nm) from a sacrificial underlayer of Cu. It is demonstrated that the expansion of the anodized Ti layer... View full abstract»

• ### Spontaneously Formed FePt Graded Granular Media With a Large Gain Factor

Publication Year: 2012, Article Sequence Number: 4500104
Cited by:  Papers (3)
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In conventional magnetic recording media fabrication processes, magnetically soft regions of composite or graded material are prepared by varying either the substrate temperature or the film composition during deposition. In this work, ultrathin FePt granular media with graded composition was fabricated directly by spontaneous layer diffusion between FePt and Pt layers during the film deposition. ... View full abstract»

• ### Role of Dipolar Interactions on the Thermal Stability of High-Density Bit-Patterned Media

Publication Year: 2012, Article Sequence Number: 4500204
Cited by:  Papers (4)
| | PDF (336 KB) | HTML

We have characterized the magnetic reversal and thermal stability of bit-patterned media with a composite structure of [Co (0.25 nm)/Pd (0.7 nm)]5 /Fe(X)/[Pd (0.7 nm)/Co (0.25 nm)] 5, where X = 1, 1.5 , and 2 nm. For 25 nm diameter islands separated by 35 nm, the average thermal stability of the islands is confirmed by analyzing the time-dependent coercive field... View full abstract»

• ### Novel system design for readback at 10 terabits per square inch user areal density

Publication Year: 2012, Article Sequence Number: 4500304
Cited by:  Papers (4)  |  Patents (1)
| | PDF (1480 KB) | HTML

A novel system design for sensing very high density magnetic recording data, such as that envisioned for two-dimensional magnetic recording, is proposed. The key idea is a rotated sense head, so that the shields are aligned down-track, combined with oversampled signal processing to regain the lost down-track resolution. Based on a random Voronoi grain model, simulation indicates that for bits with... View full abstract»

• ### Magnetic switching properties of Fe-Ni-Pt thin films with graded magnetocrystalline anisotropy

Publication Year: 2012, Article Sequence Number: 4500404
Cited by:  Papers (1)
| | PDF (408 KB) | HTML

Exchange-coupled composites and graded magnetocrystalline anisotropy Ku films allow a lower switching field while maintaining a given thermal stability relative to a conventional single Ku thin film. In this letter, [001] oriented single composition, multilayered single compositions, and a linearly graded composition of L10FexNi0.48-xPt... View full abstract»

• ### Efficient Magnetic Gradient Field Generation With Arbitrary Axial Displacement for Magnetic Particle Imaging

Publication Year: 2012, Article Sequence Number: 6500104
Cited by:  Papers (5)
| | PDF (1460 KB) | HTML

The magnetic particle imaging method applies a magnetic gradient field featuring a field-free point (FFP) to determine the spatial distribution of superparamagnetic nanoparticles. Such a field is generated by two opposing electromagnetic coils, carrying currents in opposite directions. To achieve a large field of view, the FFP needs to be shifted in space. This can be realized by superimposing cur... View full abstract»

## Aims & Scope

IEEE Magnetics Letters is a peer-reviewed, archival journal covering the physics and engineering of magnetism, magnetic materials, applied magnetics, design and application of magnetic devices, bio-magnetics, magneto-electronics, and spin electronics.

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## Meet Our Editors

Editor
Ron B. Goldfarb
National Institute of Standards and Technology