Heat-assisted interlaced magnetic recording (HIMR) further increases recording density compared to heat-assisted magnetic recording due to the interlaced track layout. However, the smaller circular thermal profile of the top low-temperature-written tracks results in severe transition curvatures, which causes nonlinear distortions of the readback signal and degrades the bit error rate (BER) performance

This letter demonstrates the fabrication and characterization of externally switchable electro-permanent magnets (EPMs) microfabricated on silicon wafers. Each EPM comprises a thick-film bilayer of electroplated cobalt-platinum as the hard magnetic phase and screen-printed aluminum-nickel-cobalt/polydimethylsiloxane composite as the soft magnetic phase. The selected magnetic materials and corresponding

This letter presents the design, modeling, and optimization of a bistable electromagnetic actuator of size 2.2 mm × 2.2 mm, consisting of a hard magnet membrane, a planar coil, and a permanent magnet. An analytical model is established to calculate the magnetic field generated by the coil, which is validated by the finite-element method. Based on the theoretical analysis of magnetic force, the actuator's

Scavenging mechanical energy from ubiquitous vibrations through miniaturized electromagnetic (EM) transducers is a potential solution to the problem of powering wireless sensor networks for the Internet of Things (IoT). This letter presents the design and performance analysis of fully integrated EM vibration energy harvesters on the scale of microelectromechanical systems (MEMS). Through analytical

The anomalous behavior of the frequency $f$ and specific heat ${C_p}$ data for the new layered trigonal ( $P\bar{3}1m$ ) form of manganese antimonite (MnSb 2 O 6 ) was analyzed by means of the power-law relations with the critical exponent $\alpha $ in the vicinity of the Néel temperature of ${T_{\rm{N}}}$ = 8.0 K. While the extracted values of $\alpha $ from both $f$ and ${C_p}$ below $T_{\rm{N}}$

A single resonance-type spin-torque microwave diode (STMD) can be used as a quadratic detector to determine the frequency $f$ of an external microwave signal when the power $P_{\rm rf}$ of this signal is known. However, unless the signal's frequency $f$ exactly coincides with the detector's resonance frequency $f_{\rm res}$ , there exists a finite frequency determination error $\Delta f$ . In this

Despite the vast hardware resources available in field-programmable gate arrays (FPGAs), the implementation of very large and complex designs on these platforms is a challenging problem. One effective solution is to use task scheduling. In this method, the FPGA configuration is changed according to the required task. This requires access to external nonvolatile memory, which significantly reduces system

Spin-torque ferromagnetic resonance (ST-FMR), particularly using magnetic insulators and heavy metals possessing a giant spin Hall effect (SHE), has received a lot of attention for the development of spintronic devices. To devise complex functional devices, it is necessary to construct the equivalent spin-circuit representations of different phenomena. Such representations are useful for translating

The effect of temperature on negatively charged nitrogen-vacancy (NV) centers in diamond is interesting owing to their high precision and high spatial resolution. In addition, this thermal effect has many applications, such as in magnetic imaging, materials science, and fundamental physics. Temperature sensitivity varies for different magnetic field directions. In this letter, a temperature working

Perpendicular shape anisotropy spin-transfer-torque magnetic random-access memory (PSA-STT-MRAM) demonstrates high thermal stability when size is reduced to 20 nm, which gives a new way to improve the integrity of electronic devices. This long and narrow device also poses challenges in the device fabrication process, such as sample tilt and etching defects. We used a micromagnetic simulation method

A branch connecting two neighboring ferromagnetic α 1 -phase rods is one of the geometric factors that contributes to degradation of alnico's normally high coercivity. This letter investigates the effects of various branch geometries and dimensions on the coercivity of alnico comprehensively by using a micromagnetic simulator when the branch is assumed to be connected in either H- or U-shaped alnico

In this letter, we report on the magnetic and structural properties of Y 3 Fe 5 O 12 (YIG) thin films deposited on a thermally oxidized silicon substrate. Broadband ferromagnetic measurements allowed us to distinguish between intrinsic and extrinsic linewidth contributions, revealing relatively low values of the Gilbert damping parameter that is in the range of 10–20 × 10 -4 for film thicknesses below

Recently, magnetic tunnel junctions (MTJs) with superparamagnetic free layers (sMTJs) have been proposed as key components in probabilistic bits (p-bits). However, the average fluctuation rates of sMTJs are very sensitive to slight variations in the device dimensions, which creates a major obstacle to their realization in large-scale networks. One possible solution is to implement dual-biasing on p-bits

We measured saturated hysteresis loops of a MuMETAL ring using a computerized, high-resolution apparatus by both extrapolated continuous recording and automatic ballistic methods. The recording time per loop varied from 17.7 to 141.6 s. The loops obtained for short recording times were significantly wider than the loop obtained by the ballistic method. By extrapolating the magnetic field of different

This letter focuses on improvements in the performance of flat-wire coils for wireless power transfer in smartphones based on the Qi interface standard. At high frequencies, alternating-current copper losses increase due to the proximity and skin effects. A low-permeability magnetic composite with low hysteresis loss was applied to a coil to reduce coil losses. A parametric analysis was used to obtain

Hardware implementation of artificial neural networks (ANNs) using conventional binary arithmetic units requires large area and energy, due to the massive multiplication and addition operations in the inference process, limiting their use in edge computing and emerging Internet of Things (IoT) systems. Stochastic computing (SC), where the probability of 1s and 0s in a randomly generated bit-stream

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

In this letter, a novel-feature-based simultaneous localization and mapping (SLAM) approach based on detection of magnetic beacons is presented as a convenient and accurate navigation solution. The magnetic beacons can be accurately detected with unknown background magnetic field by modeling the background field with polynomials and performing joint estimation. By taking the beacons as landmarks, a

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

Magnetic particle imaging (MPI) provides three-dimensional decoding of magnetic materials. In MPI, the field-free line (FFL) selection field method offers a spatial encoding across a line, which reduces acquisition time, improves sensitivity, and increases the signal-to-noise ratio. Permanent magnets of Halbach layout are interesting for the use in MPI owing to their advantages, such as an alternative

Presents the front cover for this issue of the publication.

Presents the 2020 subject/author index for this 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.

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 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

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

ZnFe2O4/CuFe2O4 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 ZnFe2O4/CuFe2O4 composite crystallites with cubic phase of ZnFe2O4 and tetragonal phase of CuFe2O4. Scanning electron microscopy revealed the formation of octahedral polycrystals of zinc-copper

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/in2. 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 (MoS2) is a significant material yet to be explored for its magnetic properties. In this letter, thin films of MoS2 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 of

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 Zn0.4Fe2.6O4 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 for both

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 L10 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 L10 FePd; among them are substrate, deposition temperature

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 (Hg0.865Mn0.135Te) 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