Neuromorphic computing with spintronic devices has been of interest due to the limitations of CMOS-driven von Neumann computing. Domain wall–magnetic tunnel junction (DW-MTJ) devices have been shown to be able to intrinsically capture biological neuron behavior. Edgy-relaxed behavior, where a frequently firing neuron experiences a lower action potential threshold, may provide additional artificial

In this letter, a deep-learning-based neural network for magnetic dipole modeling (MDMnet) is introduced in the framework of dc magnetic cleanliness for space missions. The developed method targets modeling the static magnetic signature of a spacecraft unit that is obtained during the unit-level characterization stage of the extensive prelaunch electromagnetic compatibility test campaign. By employing

In this letter, we report the use of optically addressable spin centers in SiC to probe the static magnetic stray fields generated by a ferromagnetic microstructure lithographically patterned on the surface of a SiC crystal. The stray fields cause shifts in the resonance frequency of the spin centers. The spin resonance in the spin centers is driven by a micrometer-sized microwave antenna patterned

In this letter, we demonstrate a low-cost fiber loop ring-down (FLRD) magnetic field sensor using frequency-shifted interferometry. A D-shaped fiber coated with magnetic fluid was used as the sensor head for enhancing the sensitivity and improving the stability. With this scheme, the magnetic field was sensed in the space domain by measuring the ring-down distance, and its measurement accuracy was

Spin-momentum locking in the surface mode of topological insulators leads to the surface accumulations of spin-polarized electrons caused by bias currents through topological insulator samples. It is demonstrated in this letter that surface spin-polarized electron accumulations caused by the above bias currents can be sensed by using scanning tunneling microscopy. The experimental results of this sensing

Spin-orbit torque (SOT) offers ultrafast magnetic switching in the subnanosecond regime for magnetoresistive random-access memory (MRAM) as an alternative to future cache memories. However, one main obstacle to the development of perpendicular SOT-MRAM is that a small in-plane external field is required to achieve deterministic magnetization switching. Here we eliminate the external magnetic field

In this letter, we present a numerical approach to obtain the ferromagnetic resonance spectra of micrometer- and nanometer-sized magnetic elements by micromagnetic simulations. By mimicking common experimental conditions, we applied a static magnetic field and used a linearly polarized oscillating magnetic field to excite magnetization dynamics. A continuous single-frequency excitation is utilized

Spin-orbit torque (SOT) has been widely used in data writing of spintronic memory devices by current-induced magnetization switching. The typical structure of SOT-induced magnetization switching of ferromagnetic multilayers with perpendicular magnetic anisotropy such as Ta/CoFeB/MgO allowed the ferromagnetic and adjacent nonmagnetic layer to be patterned independently. In this letter, we study the

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Presents the 2020 subject/author index for this publication.

In this letter, the effect of transition metal (TM) adsorption on the magnetic and electronic properties of borophene nanosheets is investigated. The borophene surface is modified by TMs, and its characteristics are evaluated using density functional theory. The appropriate site for TM adsorption is calculated on the middle of a hexagonal loop (H site). The binding energies between the adsorbed TMs

Thin Vicalloy wires with bistable magnetization states exhibit a fast magnetization reversal when excited by an external magnetic field. The reversal is accompanied by a large Barkhausen jump that is independent on the rate of change of the external field. For indirect observation of the large Barkhausen jump and for many sensor applications, a pickup coil is used in general. The amplitude of the voltage

For an ultrahigh areal-density bit-patterned magnetic recording, system performance is severely degraded by intertrack interference (ITI). Rate-4/5 and rate-5/6 modulation codes were introduced to avoid data patterns that can cause severe ITI. However, their decoders might not be able to correctly perform for data patterns that do not match with their look-up tables during the decoding process. To

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

Cover photograph of J. M. D. Coey by John Kelly, 2007; courtesy of School of Physics, Trinity College Dublin, all rights

In this letter, the influence of spin-transfer torque (STT) on magnetic read sensor noise in the test band of 1–200 MHz has been investigated experimentally using the macrospin model with STT term. The results reveal a dependence of the integrated noise power on the direction of bias current when an external field is applied. In a positive field direction, positive bias current produces stronger noise

This letter describes an electromagnetic feedback control system for rigid-body motion control of a magnet. Its novel features are that sensing and actuation using magnetometer sensors and actuator coils operate simultaneously. Magnetic field models from the controlled magnet and each of the actuator coil currents are used together to calculate the three-dimensional position and orientation of the

The magnetic field inside a spherical magnetic shield with infinite permeability and a circular aperture in a homogeneous magnetic field of arbitrary direction is analytically derived. The closed-form formulas for the static shielding factors are theoretical upper limits for real shields. We discuss the magnetic field gradient inside the shield caused by a single aperture, implying that using symmetric

ZnFe 2 O 4 /CuFe 2 O 4 composites in the ratios of 0.95:0.05 and 0.5:0.5 were synthesized via coprecipitation technique using polyvinyl alcohol as a surfactant. The X-ray diffraction study revealed the formation of nanosized ZnFe 2 O 4 /CuFe 2 O 4 composite crystallites with cubic phase of ZnFe 2 O 4 and tetragonal phase of CuFe 2 O 4. Scanning electron microscopy revealed the formation of octahedral

Quaternary memory and logic circuits have been studied by researchers, as they can provide denser integrated circuits and subsequently lower area and power consumption via succinct interconnects. Using multithreshold gate-all-around carbon nanotube field-effect transistors and the nonvolatile feature of magnetic tunnel junctions (MTJs), this letter proposes a bio-inspired variation-aware nonvolatile

In this letter, we use magnetooptical Kerr effect magnetometry on extended samples to measure local hysteresis curves as a function of an externally applied field in a magnetostriction-free amorphous ribbon and an elliptical Permalloy film element. Although these materials are magnetically soft and have almost zero coercive field, we find that the local hysteresis curves have a highly nonlinear hysteretic

We examined the microstructural parameter $\ \alpha $ in order to investigate the influence of its components on the intrinsic coercivity of an isotropic Nd-Fe-B sintered magnet. By applying boundary conditions for the assessment of grain (mis)alignment ${\alpha _\psi }$ and exchange coupling ${\alpha _{exc}}$ and combining with magnetic measurements and structural characterization results obtained

Bit-patterned media recording (BPMR) is one of the most promising candidates to further increase recording density beyond 1 Tb/in 2 . For high-density BPMR systems, severe intertrack interference (ITI) and media noise caused by decreased track pitch bring severe deterioration to the readback signals. To mitigate the impact of ITI and media noise on bit error rate (BER) performance, we developed a multitrack

Molybdenum disulfide (MoS 2 ) is a significant material yet to be explored for its magnetic properties. In this letter, thin films of MoS 2 are grown on n-silicon substrates via a spin coating method. Deposited films are magnetically annealed at 200 °C with a varying magnetic field from 280 to 520 G. Furthermore, the effect of magnetic field annealing on the structural and magnetization properties

In this letter we study magnetization reversal and transformation of magnetic domain structures in glass-covered magnetic microwires. Studies were performed using the magneto-optical Kerr effect technique in the presence of the combination of tension and torsion mechanical stresses. Formation and reversible transformations of the surface helical structure, induced by the combined stress, were found

This letter discusses the temperature dependence of the magnetic field at which irreversible magnetic flux loss of ferrite sintered magnets is initiated. In this material class such a field might reduce linearly: comparable behavior to that observed for Nd-Fe-B-based sintered counterparts increases linearly or even peaks for temperatures above 350 K. These differences are attributed to variations in

We investigated the static and dynamic magnetic properties of Zn 0.4 Fe 2.6 O 4 nanoparticles synthesized by thermal decomposition. Two ranges of diameter were used: small particles (diameter about 6.2 nm) and larger ones (diameter about 22.4 nm). The nanoparticle microstructure was characterized by transmission electron microscopy. The temperature dependence of the zero-field dynamic permeability

We analyze the scalability of a spin–orbit torque random access memory (SOT-MRAM)-based physical unclonable function (PUF) at the nanoscale size by means of a hybrid CMOS/spintronics simulation framework. The properties of the SOT-MRAM device (diameters from 100 nm down to 25 nm) are computed via micromagnetic simulations, whereas their implications for PUF applications are evaluated at the circuit

An analog microwave signal correlator, based on parametric pumping of a spin wave by a radio frequency (RF) magnetic field, is demonstrated. The binary codes to be correlated modulate the two microwave signals input to the device to, respectively, excite the spin wave and RF field at twice the carrier frequency of the spin wave. The magnetic field parametrically pumps the spin wave, generating a counterpropagating

We introduce a formulation of a two-sublattice micromagnetic model, which can describe the statics and dynamics of ferromagnets, antiferromagnets, and ferrimagnets. Such a formulation is based on the normalization of exchange, Dzyaloshinskii–Moriya interaction, and anisotropy parameters with respect to the square modulus of the saturation magnetization for each sublattice. We show a study of the statics

Losses in magnetic circuits are closely related to reluctance. Dealing with coils, transformers, stator poles, rotors in motors, and electromagnets with iron slabs in electrical actuators may raise the question regarding the effect of the slope of section profiles on losses and performance. In this letter, with dc and ac sources, through injective section profiles, we obtain complex, negative, and

Materials such as L 1 0 Fe-based alloys with perpendicular magnetic anisotropy derived from crystal structure have the potential to deliver higher thermal stability of magnetic memory elements compared to materials whose anisotropy is derived from surfaces and interfaces. A number of processing parameters enable control of the quality and texture of L 1 0 FePd; among them are substrate, deposition

We demonstrate a technical solution to achieve an intense 50 Hz alternating magnetic field and a static magnetic field made by a permanent magnet at the same place. A compact coil built using the Bitter coil concept is customized to support alternating current, thus creating an alternating magnetic field. A complementary permanent magnet assembly is built around it to achieve the superposition of both

Track misregistration (TMR) is one of several problems in ultrahigh areal density bit-patterned magnetic recording (BPMR) systems, in which the distances between bit-islands are very narrow in both cross-track and down-track directions. Unfortunately, distance reduction leads to intersymbol interference and intertrack interference (ITI) effects, which cause system performance degradation. To deal with

In this letter, a model of strain-induced nanomagnet at room temperature is established to explore the effect of size error on the reliability of straintronic memory and spin neurons. The results show that the relationship between input voltages and 180° magnetization switching probability (activation function) of the nanomagnet has a size dependence. The slope of the activation function is related

Heat-assisted magnetic recording is a future hard disk drive (HDD) technology for extremely increasing areal density. The tunneling magnetoresistive (TMR) device structure, located inside the magnetic read–write head of a hard drive, is the most complex and sensitive component, which contains sensitive components, such as a touchdown sensor and a near-field transducer. The laser used in the writing

We present an experimental system aimed at mapping the magnetic field created by a ring magnet in the working region of a single-magnet magnetic levitation system. The key idea is based on the photoregistration of a transparent air-filled cavity formed in a thin magnetic fluid layer due to balancing the gas pressure and the pressure emerging due to magnetic forces. As a result, the contour of the magnetic

Recent advances in additive direct-write circuit technology have enabled the fabrication of inductive winding geometries previously considered impossible by conventional methods. In this letter, a winding fabricated around a rectangular cross-section toroidal core is considered. As an extension of research embedding toroidal cores within printed circuit board, this letter considers the minimization

Mercury chalcogenide (Hg 0.865 Mn 0.135 Te) monocrystal was grown by crystallization from a two-phase mixture with replenishment of the melt from a tellurium solution and has n-type conductivity. The electron spin resonance (ESR) spectra of a single crystal were studied before and after X-irradiation. Only one intense anisotropic ESR line was observed at 4.2 K before X-irradiation. The anisotropy parameters

Among magnetic alloys, Alumel (95%Ni-2%Mn-2%Al-1%Si) has been widely used due to its technological applications. We fit the specific heat, at zero magnetic field, of this alloy by the Blume-Capel model for spin $\sigma =1$ on a two- and three-dimensional cubic lattice, using Monte Carlo simulation. The best results obtained on a square lattice (linear dimension $L=512$ and 1000 Monte Carlo steps per

This letter studies the formation of a skyrmion crystal with a noncollinear magneto-electric interaction at the interface between a ferroelectric layer and a magnetic layer with triangular lattice in a ferromagnetic/ferroelectric superlattice and its phase transition. The ground-state spin configuration is calculated by using the steepest descent method. We noted that for zero applied magnetic field

The effect of annealing temperatures on the tunnel magnetoresistance (TMR) of MgO-based magnetic tunnel junctions (MTJs) has been investigated for annealing between 190 and 370°C. The TMR shows a maximum value of 215% at an annealing temperature of 330°C. A strong sensitivity of the TMR and the exchange bias of the pinned ferromagnetic layers on the annealing temperature are observed. Depending on

The Halbach array magnetization of thick-film Nd–Fe–B magnets using local laser irradiation is examined. A 75 µm thick isotropic Nd–Fe–B magnet is deposited on a Si substrate by pulsed laser deposition and used to form microlinear Halbach arrays. The micromagnetization patterning of the Halbach arrays is realized by a combination of pulsed magnetization and laser-assisted heating with changing the

Shingled magnetic recording (SMR) is regarded as the most influential technology for the next-generation magnetic recording systems. The SMR tracks are partly overlapped by each other, and the SMR systems can obtain higher area densities by increasing track per inch density. As a result, this brings more interference from the adjacent sidetracks, i.e., intertrack interference (ITI) while reading the

The various memory applications such as embedded nonvolatile memory, embedded static random-access memory, and standalone dynamic random-access memory have different requirements for the performance of the perpendicular magnetic tunnel junction (pMTJ). However, in conventional pMTJ structures, the write current and stability of the free layer are directly coupled, leading to undesirable tradeoffs in

Mn–Bi alloys modified with Mg and other elements were recently developed into promising rare-earth-free permanent magnets through successive melt spinning, warm compaction, and short magnetic field annealing. This letter reports on the crystal structures, texture, and magnetic properties observed in Mn 50 Bi 49- $x$ Mg $x$ Sb 0.5 In 0.5 alloys ( $x$ = 0, 1.5, 3.0, 4.5) throughout these processing steps

In the practical application of high-temperature superconducting (HTS) magnetic levitation, the influence of ambient temperature on its performance is mainly reflected in the change of magnetic characteristics of the permanent magnet guideway (PMG). In order to investigate the magnetic characteristics of the PMG at high temperature and the influence of temperature on the levitation performance of HTS

The influence of the materials that construct a one-dimensional magnetophotonic crystal (MPC) is investigated in this letter. Recently, we suggested a procedure for realizing a desirable magneto-optical performance by utilizing an MPC heterostructure. The performance to be realized consists of a desirable transmittance along with a desirable Faraday rotation angle. The synthesis procedure gives the

There has been no study for measuring the comprehensive flow field of magnetic fluids. A pumpless transport system has been envisaged based on the temperature dependence of the magnetization of magnetic fluid; however, the knowledge regarding the internal flow is still limited. It is difficult to optimize the design and realize the practical use of the transport system using magnetic fluid. Therefore

In the heat-assisted magnetic recording (HAMR) process, the transition jitter is known to depend on the grain size as well as the heat spot thermal gradient. We find that the jitter also depends on the Voronoi grain size distribution, as well as exhibiting a surprising nonlinear dependence on reader width. By combining the noise due to these dependencies we used an analytical formulation to estimate

This letter presents a novel speed sensor based on motion-induced eddy currents in conductive moving parts. The magnetic yoke is an E-shaped ferrite core. The excitation coil is on the center leg of the E-core, and two antiserially connected pick-up coils are on the side legs. Solid iron and aluminum materials are used for the moving part in the simulations and in the measurements. Two-dimensional

In a bit-patterned media recording (BPMR) system, reducing the spacing between adjacent bit islands in the down- and cross-track directions increases areal density; however, two-dimensional (2-D) interference comprising intersymbol and intertrack interferences degrades the system performance. To mitigate error patterns that increase the 2-D interference in BPMRs, 2-D modulation coding schemes have

We report on magnetic properties of Fe–Ni–Ti alloys after severe plastic deformation (SPD) by high-pressure torsion (HPT) and low-temperature annealing. SPD and low-temperature annealing considerably change the magnetization behavior. The main magnetic and structural characteristics of bulk and HPT materials were determined. The addition of small amounts of Ti and annealing at 300 °C will not lead

Bit-patterned media recording (BPMR) is a candidate technology that extends the density to up to 4 Tb/in 2 to handle large amounts of data. However, in BPMR systems, the major challenge is two-dimensional (2-D) interference, which includes intersymbol interference from the down-track direction and intertrack interference from the across-track direction. To combat 2-D interference, it is natural to

This letter reports the development of low-damping yttrium-iron-garnet (YIG) thin films via sputtering. The films were deposited by sputtering at room temperature first and were then annealed in O 2 at high temperature. It is found that the annealing temperature critically affects the structural properties of the YIG films and thereby dictates the static and dynamic properties of the films. A 75 nm

Integration of yttrium iron garnet (YIG) with Si can bring new avenues for garnet-based complementary metal-oxide semiconductor compatible devices. Herein, investigations on the morphological, electrical, and magnetic properties of postgrowth annealed YIG thin films grown on Si substrate were systematically performed at nanoscale lateral resolution, employing the variants of atomic force microscopy

Spectral, temperature, and magnetic field dependences of the magneto-optical transversal Kerr effect (TKE) as well as optical properties of (In,Mn)As samples prepared by ion implantation followed by pulsed laser melting were studied, and a strong TKE response was detected at low temperatures. The presence of a characteristic structure in the TKE spectra in the transition region around the Λ point of

We present the fabrication process and characterization of a tunnel magnetoresistance sensor-based monolithic device assembled in Wheatstone bridge architecture, capable of measuring magnetic fields in both planar-sensitive directions simultaneously. This process is simplified in comparison with other fabrication strategies, as it does not require annealing or the usage of auxiliary structures to achieve

In this letter, we examine underwater wireless communications using electromagnetic waves in marine shallow waters. Due to the particular environment under study (low frequencies, short distances, and small loop antennas), a magnetoquasi-static approach is used instead of full-wave analysis. The electric field generated by a constant current circular loop placed on the interface between two conductors