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Design and testing of a compact, portable sTMS device IEEE Magn. Lett. (IF 1.2) Pub Date : 2024-02-28 Wesley Lawson
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Radiation-Immune Spintronic Binary Synapse and Neuron for Process-in-Memory Architecture IEEE Magn. Lett. (IF 1.2) Pub Date : 2024-01-22 Milad Tanavardi Nasab, Abdolah Amirany, Mohammad Hossein Moaiyeri, Kian Jafari
This letter proposes a single event upset (SEU)-hardened task-scheduling logic-in-memory xnor/xor neuron and synapse circuit. Using a C-element and a magnetic tunnel junction enhances immunity against SEU injection. Also, using logic-in-memory architecture eliminates the need to access external memory and decreases power and delay. Furthermore, using a carbon nanotube field-effect transistor leads
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Magnetic Field-Induced Phase Transition and Weak Ferromagnetism in Nonsuperconducting Optimally Doped PrBCO Cuprate IEEE Magn. Lett. (IF 1.2) Pub Date : 2024-01-05 Mahieddine Lahoubi, Shengli Pu, Weinan Liu, Zhe Yang
In this letter, we report anomalous magnetic properties in high dc magnetic fields H up to 11 and 16 T from 1.35 up to 20 K on PrBa 2 Cu 3 O 6.95 (PrBCO 6.95 ) cuprate ceramic. Significant magnetic-field effects are revealed in the derivative of the magnetization M ( T ) versus T using two sets of values of H selected in the range of 2.5–9.5 T. Anomalies are observed at the low-critical point T cr
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Antiferromagnetism in Two-Dimensional, 1T-Phase Iridium Oxide IEEE Magn. Lett. (IF 1.2) Pub Date : 2024-01-05 Charlie Jindrich, Qi Shao, Antonio Ruotolo
Theoretical studies show that metastable phases of nonmagnetic oxides could exhibit magnetic order when synthesized in two-dimensional (2-D) atomic crystals. In this letter, we report experimental evidence of a nontrivial antiferromagnetic behavior in a 2-D, metastable phase of iridium oxide in which iridium forms a triangular lattice. We compare the magnetic behavior of the crystals in the morphology
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Microstructure Evolution and First-Order Reversal Curve Analysis of the Interphase Coupling in SmCo Thick Film IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-12-18 Oksana Koplak, Federico Maspero, Alejandro Plaza, Andrea Del Giacco, Maria Cocconcelli, Riccardo Bertacco
Thick SmCo films of 500 nm thickness were deposited by radio frequency sputtering in W/SmCo/W structures on a Si substrate. After annealing at 650–750 °C, the as-grown soft amorphous structure transforms into a mixture of crystalline Sm 2 Co 17 and SmCo 5 hard magnetic phases. Annealing at 650 °C leads to film crystallization with an average grain size of 64 nm, coercivity of 0.5 T, and remanence magnetization
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A Numerical Method to Determine Demagnetization Factors of Stadium-Shaped Nanoislands for Artificial Spin Ices IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-11-20 Victoria Martinez, Ezio Iacocca
The shape of nanoislands gives rise to a demagnetizing field that is primarily responsible for the orientation of the magnetization along an axis. In the context of magnetization dynamics, the demagnetization (demag) field also determines the resonant frequencies captured by Kittel's equations. Analytically, we require demag factors that can be obtained exactly for a few geometries, including ellipsoids
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A High-Sensitivity Composite Probe Capable of Simultaneously Measuring Electric- and Magnetic-Field Components IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-10-13 Lei Wang, Duan Nie, Liye Cheng, Hongyue Wang
This letter presents a high-sensitivity composite probe capable of simultaneously measuring electric- and magnetic-field components. The composite probe contains a U-shaped loop, two parasitic long loops, and a pair of strip lines as a transmission part. First, the U-shaped loop is designed to test both electric and magnetic fields. Second, two parasitic long loops are placed at both sides of the U-shaped
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Materials Informatics for the Development and Discovery of Future Magnetic Materials IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-09-29 Ryotaro Okabe, Mingda Li, Yuma Iwasaki, Nicolas Regnault, Claudia Felser, Masafumi Shirai, Alexander Kovacs, Thomas Schrefl, Atsufumi Hirohata
This letter summarizes the recent development of magnetic materials search using artificial intelligence (AI) and machine learning (ML) and briefly introduces ML and AI approaches to materials discovery. The authors offer a flowchart to aid the selection of relevant approaches for their material search. This letter also covers the authors' recent research activities in magnetism and quantum materials
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Fabrication and Characterization CoZrO Films Deposited by Facing Targets Reactive Sputtering for Micromagnetic Inductors IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-09-28 Honami Nitta, Yota Takamura, Tadayuki Kaneko, Shigeki Nakagawa
In recent years, there has been a strong demand for soft magnetic films suitable for high-frequency micromagnetic devices as power electronics circuits to operate at higher frequencies. Specifically, there is a need for magnetic thin films with ferromagnetic resonance frequencies ( f r ) in the range of several gigahertz. Nanogranular CoZrO thin films have emerged as promising candidates due to their
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Increasing Flips per Second and Speed of p-Computers by Using Dilute Magnetic Semiconductors IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-09-27 Rahnuma Rahman, Supriyo Bandyopadhyay
Probabilistic computing with binary stochastic neurons (BSNs) implemented with low-barrier magnets (LBMs) or zero-energy barrier nanoscale ferromagnets possessing in-plane magnetic anisotropy has emerged as an efficient paradigm for solving computationally hard problems. The fluctuating magnetization of an LBM at room temperature encodes a p-bit, which is the building block of a BSN. Its drawback,
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Investigation of the Soft-Magnetic Properties of CoZrTaB Laminated Cores by Dielectric Layer Tuning IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-09-26 Guannan Wei, Rajasree Das, Daniel Lordan, Marek Lorenc, Barry Clark, David P. F. Hurley, Mike Hayes, Cian O'Mathuna, Ranajit Sai, Paul McCloskey
Soft magnetic properties of thin films for use as a core material are critical for the realization of future miniaturized electromagnetic devices operating at frequencies of tens or hundreds of megahertz. Laminated stacks consisting of alternate thin layers of magnetic material and dielectric material are widely used to suppress eddy current losses that dominate, especially at a higher frequency of
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Synthesis of Hexagonal Close-Packed Cobalt Nanoparticles From Thermolysis of Cobalt Carbonyl IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-09-18 Kyohei Takahashi, Hiroshi Ito, Isao Kanada, Hiroyuki Matsumoto
Magnetic materials with low magnetic loss are required to realize both a high-frequency support and a miniaturization of radio frequency components. Hexagonal close-packed cobalt (hcp-Co) nanoparticles are considered suitable for high frequencies due to their nanoparticle morphology and high magnetocrystalline anisotropy. However, the face-centered cubic (fcc) or the ϵ phase with low magnetocrystalline
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Magnetic Susceptibility-Based Detection of Fusobacterium Nucleatum in Human Saliva IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-08-23 Kazuhiko Okita, Youcheng Pu, Loi Tonthat, Toru Murayama, Shin Yabukami, Yohei Ozawa, Seji Asamitsu, Hiroshi Okamoto, Takashi Kamei
This letter presents an innovative method for rapid and precise measurement of bacteria in liquid samples for point-of-care testing. The method utilizes the bacteria concentration-dependent ac susceptibility of magnetic nanoparticles, allowing for efficient and practical bacterial detection. The ac susceptibility of the magnetic nanoparticles/bacteria aggregate exhibits a decrease proportional to the
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A Method of Shear-Horizontal EMAT Based on Dual-Reception Magnetic Encoded Spatial Pulse Compression for Multiple Cracks Identification and Location IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-08-22 Qiangxin Li, Jian Feng, Qi Xiao, Xiong Gao
The lowest order mode of a shear-horizontal electromagnetic acoustic transducer (EMAT) typically exhibits a low signal-to-noise ratio and poor spatial resolution in defect detection. To solve this issue, this letter presents a crack identification and location method based on dual-reception magnetic encoded spatial pulse compression technology. On the one hand, the method implements spatial pulse compression
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Computing in Memory Using Doubled STT-MRAM With the Application of Binarized Neural Networks IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-08-02 Seyed Hassan Hadi Nemati, Nima Eslami, Mohammad Hossein Moaiyeri
The computing-in-memory (CiM) approach is a promising option for addressing the processor–memory data transfer bottleneck while performing data-intensive applications. In this letter, we present a novel CiM architecture based on spin-transfer torque magnetic random-access memory, which can work in computing and memory modes. In this letter, two spintronic devices are considered per cell to store the
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Development of Overlapped Designed Coils for Transcranial Magnetic Stimulations IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-07-13 Sohom Bhattacharjee, Choon Sik Cho, Dong Sik Cho
Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation technique that is used to treat a variety of neurological disorders, including major depression. The development of the deep brain TMS coil for stimulating subcortical structures expands the use of TMS beyond the stimulation of superficial cortical targets. Deep brain stimulation may have beneficial effects on neurological disorders
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High-Density 1T1D1SOT-MRAM With Multimode Ultrahigh-Speed Magnetization Switching IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-07-07 Hao Zhang, Di Wang, Long Liu, Xuefeng Zhao, Huai Lin, Changqing Xie
In this letter, we present a 1T1D1M-based (one transistor, one diode, and one magnetic tunnel junction) spin-orbit torque, magnetic random-access memory (SOT-MRAM) with multimode magnetization switching for high-density memory, ultrahigh-speed writing, and energy-efficient on-chip memory application. The conventional spin-transfer torque (STT)-MRAM or SOT-MRAM is limited by the unipolar (or bipolar)
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Effect of Moderate Static Magnetic Field on Membrane Potential of Abdominal Nerve Fiber in Metapenaeus Ensis IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-07-07 Siyuan Liu, Shupeng Liu, Yongyong Gong, Jinbo Chen, Hengyu Li, Zhizheng Wu, Ze Cui, Mei Liu, Jingtao Lei, Tao Wang
The effects of uniform and static moderate magnetic fields (0–400 mT) on the membrane potential of nerve fibers in Metapenaeus ensis shrimps were investigated. The results showed that the magnetic field caused an increase in membrane potential, eventually reaching a static state, and that effects of short-term exposure were largely reversible. A nonlinear relationship between the percentage change
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Error Characteristic Analysis and Error Source Identification of Aeromagnetic Field Gradient Tensor Measurements IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-06-28 Ke Liu, Hongsong Miao, Qiang Fu, Yuqi Pang, Yangyi Sui
Aeromagnetic gradient tensor measurement has become a powerful method in geological surveys, mineral resource exploration, and other applications due to its ability to resist temporal changes of the geomagnetic field and its ability to provide rich information and be highly efficient. Various factors may affect the quality of aeromagnetic gradient tensor measurements, including systematic errors of
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Physics-Informed Sparse Neural Network for Permanent Magnet Eddy Current Device Modeling and Analysis IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-06-22 Dazhi Wang, Sihan Wang, Deshan Kong, Jiaxing Wang, Wenhui Li, Michael Pecht
The objective is to study the prediction of the electromagnetic (EM) field and the output performance of permanent magnet eddy current devices (PMECDs) based on a physics-informed sparse neural network (PISNN). In order to achieve this goal, a unified physical model is first defined according to different types of PMECDs, which is equivalent to solving a parameterized magnetic quasi-static problem
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Performance Simulation of Multiferroic Neuron Device Driven by an Inclined Monopulse Clock IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-06-19 Shuqing Dou, Xiaokuo Yang, Jiahui Yuan, Yongshun Xia, Xin Bai, Huanqing Cui, Bo Wei
Multiferroic nanomagnet neuron devices have the advantages of ultralow power consumption and high integration, which give them promising applications in neuromorphic computing. In this letter, a multiferroic nanomagnet neuron device driven by an inclined monopulse clock is modeled. The strain field direction of the device is at an angle to the nanomagnet's long axis, and the nanomagnet's magnetic moment
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In Vivo Measurement of Cerebral SPIO Concentration in Nonhuman Primate Using Magnetic Particle Imaging Detector IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-06-01 Hui Hui, Jiaojiao Liu, Hui Zhang, Jing Zhong, Jie He, Bo Zhang, Haoran Zhang, Qin Li, Hongjun Li, Jie Tian
The purpose of this study is to develop a magnetic particle imaging (MPI) technique to directly measure time-varied cerebral superparamagnetic iron oxide nanoparticle (SPIO) concentration in rhesus macaques. A hand-held MPI detector was developed to monitor MPI signal changes at the third harmonics of the drive frequency in resting-state nonhuman primates. Phantom experiments were first performed to
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The Impact of Sample Insulation on Estimating the Heating Power of Magnetic Nanoparticles by AC Calorimetry IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-05-30 Lise G. Hanson, Bianca L. Hansen, Thomas Veile, Mathias Zambach, Niels B. Christensen, Cathrine Frandsen
Correct estimation of the heating power of magnetic nanoparticles is important for magnetic hyperthermia treatment. This letter investigates the impact of sample insulation in ac calorimetry. We show that a temperature increase in the insulation can lead to systematic errors when estimating the heating power by the corrected slope method. The errors arise if the temperature of the sample environment
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Preparation of Temperature-Sensitive Rare-Earth–Iron Alloy Fine Particles Using Mechanical Alloying and Sintering IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-05-29 Jiatong Pan, Jianfei Shentu, Chunlin He, Deqian Zeng, Feng Gao, Gjergj Dodbiba, Toyohisa Fujita
Fine magnetic particles with high saturation magnetization and a large temperature-sensitive magnetization in the temperature range 300–400 K were prepared for use in temperature-sensitive magnetorheological fluids. Two methods, namely high-energy ball milling (HEBM) and sintering followed by HEBM to produce mechanochemical alloys, were used to produce R 2 Fe 17 component particles. The prepared particles
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Analysis of Skyrmion Shuffling Chamber Stochasticity for Neuromorphic Computing Applications IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-05-25 Zulfidin Khodzhaev, Emrah Turgut, Jean Anne C. Incorvia
In this study, micromagnetic simulations of a magnetic skyrmion reshuffling chamber for probabilistic computing applications are performed. The skyrmion shuffling chamber is modeled with a custom current density masking technique to capture current density variation, grain boundary variations, and anisotropy changes. The results show that the skyrmion oscillatory dynamics contribute to the system's
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A Deep Dive Into the Computational Fidelity of High-Variability Low Energy Barrier Magnet Technology for Accelerating Optimization and Bayesian Problems IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-05-08 Md Golam Morshed, Samiran Ganguly, Avik W. Ghosh
Low energy barrier magnet (LBM) technology has recently been proposed as a candidate for accelerating algorithms based on energy minimization and probabilistic graphs because their physical characteristics have a one-to-one mapping onto the primitives of these algorithms. Many of these algorithms have a much higher tolerance for error compared to high-accuracy numerical computation. LBM, however, is
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Possible Ground States and Magnetic-Field-Tuned Phase Transitions of a Geometrically Frustrated Ising Antiferromagnet on a Triangular Lattice IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-05-08 Thao Huong Pham
Possible average alignments of the spins in the ground state and the phase transitions of a geometrically frustrated Ising antiferromagnet in the presence of magnetic fields on a triangular lattice are studied in a mean field approximation. Starting from a zero-field clock phase, we can determine the phase boundaries from the curves of magnetic moments and their derivatives as functions of the fields
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Unidirectional Pore Formation in Resins Using a Magnetic-Nanoparticle-Chain Template IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-04-20 Atsuki Kobayashi, Kohya Sano, Junpei Sakurai, Hosei Nagano, Seiichi Hata, Chiemi Oka
We present a novel manufacturing technique for generating unidirectional pores in ultraviolet (UV)-curable resins using self-assembled magnetic nanoparticles (MNPs) with chain-like structures. The method utilizes two templation mechanisms for pore formation: the UV-masking effect of the MNP chains and the physical presence of MNP chains themselves. Fe 3 O 4 nanoparticles and PAK-01 were used as the
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Magnetic Field Enhancement of Water Evaporation in Confined Spaces IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-04-04 Sruthy Poulose, Yara Alvarez-Braña, Lourdes Basabel-Desmonts, Fernando Benito-Lopez, John Michael David Coey
Water is studied in confined environments where it evaporates into its own vapor. Simultaneous experiments are conducted for 0.4–0.5 µL droplets confined at the center of 54 mm long microchannels with a cross section of 0.38 mm 2 in the presence and absence of a 300 mT magnetic field. Results are compared with those for water in half-filled 100 mL beakers. The magnetic enhancement of the evaporation
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Magnetic Relaxation of Superparamagnetic Fe Oxide Particles Studied With Mössbauer Spectroscopy IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-04-03 Eiji Kita, Reisho Onodera, Mikio Kishimoto, Hideto Yanagihara
A Mössbauer spectroscopy (MS) study was performed on the superparamagnetic commercially available magnetic fluid, Resovist, with temperatures varying between room temperature and 2.6 K. Two samples were prepared for MS study, one dried specimen and the other frozen. At the lowest temperature of 2.6 K, the spectrum was characteristic of maghemite, and superparamagnetic relaxation was observed with increasing
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Crystal Structure and Magnetic Properties of Hexagonal FeCo Nitrides Prepared Using Ammonia Gas Nitrification IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-03-27 Chihiro Kodaka, Mikio Kishimoto, Eiji Kita, Hideto Yanagihara
Single-phase $\varepsilon$ -(FeCo) x N compound particles with $x$ = 2.25–2.48 were synthesized using ammonia gas nitrification. The mass magnetization $M$ at 10 K under a magnetic field of 9 T was 77 A $\cdot$ m $^{2}$ /kg, and Curie temperature $T$ C was 100 K for $x$ = 2.48. These values decreased with increasing nitrogen content. Compared with $\varepsilon$ -Fe x N, (FeCo) x N had significantly
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Magnetic-Particle-Discrimination Method Using Difference of Relaxation Time for Magnetic Particle Imaging IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-02-09 Kota Nomura, Masaomi Washino, Tetsuya Matsuda, Shun Tonooka, Seino Satoshi, H. Yoshida, K. Nishigaki, Takashi Nakagawa, Toshihiko Kiwa
Magnetic particle imaging (MPI) is an imaging modality that directly detects the nonlinear responses of magnetic nanoparticles (MNPs). Spatial encoding is achieved by saturating the magnetic moment of MNPs almost everywhere except in a special point called the field-free region in which a magnetic field vanishes. Recently, MPI sensitivity was improved using a field-free line (FFL) in which a field-free
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Magnetic Structural Analysis of Nanocrystalline Soft Magnets by Small-Angle Neutron Scattering IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-02-03 Hiroaki Mamiya, Yojiro Oba, Kosuke Hiroi, Takayuki Miyatake, Ravi Gautam, Hossein Sepehri-Amin, Tadakatsu Ohkubo
Nanocrystalline soft magnets have attracted significant attention for their improvement of energy conversion devices. It has been considered that the partial nanocrystallization of amorphous structures is a key to macroscopic magnetic softness. However, the mechanism has not been clarified because of inadequate knowledge of the magnetic nanostructures connecting microscopic crystalline structures and
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Hybrid MTJ/CNTFET-Based Binary Synapse and Neuron for Process-in-Memory Architecture IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-01-19 Milad Tanavardi Nasab, Arefe Amirany, Mohammad Hossein Moaiyeri, Kian Jafari
This letter develops a reliable, integrated binary synapse and neuron model for hardware implementation of binary neural networks. Thanks to the nonvolatile nature of magnetic tunnel junctions and the unique features of carbon nanotube field-effect transistors, the modeled design does not require external memory to store weights and also consumes low static power. Also, due to the circuit structure
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Impact of Array Length on Particle Attraction in Magnetic Drug Targeting: Investigation Using an Exponential Approximation of the Magnetic Field IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-01-16 Angelika S. Thalmayer, Kilian Götz, Samuel Zeising, Georg Fischer
In magnetic drug targeting, special magnetic nanoparticles that carry the anticancer drug are injected into the cardiovascular system in the vicinity of the tumor and are navigated into the tumor using a magnetic field. Many researchers optimize single magnets for this purpose; however, magnetic arrays that are placed parallel to the vessel in order to increase the impact time of the magnetic force
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Investigation of Impact of the Annealing on Magnetothermal Properties of Zn0.2Mn0.8Fe2O4 Nanoparticles IEEE Magn. Lett. (IF 1.2) Pub Date : 2023-01-02 Nan N. Liu, Yulia A. Alekhina, Alexander P. Pyatakov, Nikolai S. Perov, Boris B. Kovalev, Gleb B. Sukhorukov, Alexander M. Tishin, Tomomasa Moriwaki, Kenta Nakazawa, Yuko Ichiyanagi
Magnetic and magnetothermal properties of annealed Zn 0.2 Mn 0.8 Fe 2 O 4 nanoparticles with diameter value, ranging from 9 to 35 nm, have been investigated and compared with earlier investigated unannealed Zn 0.2 Mn 0.8 Fe 2 O 4 magnetic nanoparticles (MNPs). A single-phase spinel structure was observed in both types of MNPs. It has been demonstrated that for the large annealed Zn 0.2 Mn 0.8 Fe 2
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Numerical Study on the Magnetization Characteristics of Chainlike Magnetic Nanoparticles IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-12-23 Haochen Zhang, Yi Sun, Zhongzhou Du, Teruyoshi Sasayama, Takashi Yoshida
This work investigated chainlike magnetic nanoparticles (CMNPs), which are a type of magnetic nanoparticle (MNP) with a dipole–dipole interaction in which individual nanoparticles are connected to form a chainlike structure. We numerically analyzed the ac magnetization characteristics of the CMNP and the single-core MNP (SMNP) using the Landau–Lifshitz–Gilbert equation. Owing to the magnetic dipole–dipole
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Integration of Novel High-Frequency Transformer With Silicon-Carbide Schottky Diodes IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-12-14 Weichong Yao, Junwei Lu, Andrew Seagar, Feifei Bai, Foad Taghizadeh
This letter presents a novel and compact structure that integrates silicon-carbide (SiC) Schottky diodes within a high-frequency transformer (HFT). The proposed structure would reduce the volume of a power converter and, in turn, the system to which it is applied. It would also greatly reduce the leakage inductances of an HFT as well as the inductive electromagnetic interference to surrounding components
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Effect of Gas Composition During Pt Sputtering on Structural and Magnetic Properties of CoFeB Thin Films IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-12-13 Hans T. Nembach, Justin M. Shaw, Chloe S. Taylor, Daniel B. Gopman
Ultrathin Ta/CoFeB/Pt trilayer structures are relevant to a wide range of spintronic applications, from magnetic tunnel junctions to skyrmionics devices. Controlling the perpendicular magnetic anisotropy, Gilbert damping, and Dzyaloshinskii–Moriya interaction (DMI) in the CoFeB layer is key for these applications. We examine the role of sputter gas composition during the Pt overlayer deposition of
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Influence of Dzyaloshinskii–Moriya and Dipole–Dipole Interactions on Spontaneous Magnetization Reversal Time of Finite-Length Co Chains on Pt(664) Surfaces IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-12-05 Sergey V. Kolesnikov, Ekaterina S. Sapronova
The spontaneous magnetization reversal of the finite-length Co chains on Pt(664) surface is investigated in the framework of the classical effective theory. The effective theory includes the Heisenberg exchange interaction, magnetic anisotropy energy, Dzyaloshinskii–Moriya interaction (DMI), and dipole–dipole interaction. The geodesic-nudged elastic band method is employed for calculations of the energy
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Mean-Field Modeling of Magnetocaloric Effect of Antiferromagnetic Compounds IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-12-05 B. P. Alho, P. O. Ribeiro, R. S. de Oliveira, V. S. R. de Sousa, E. P. Nóbrega, B. C. Margato, J. M. N. da Silva, P. J. von Ranke
Antiferromagnetic compounds are known in the literature to present the inverse magnetocaloric effect (MCE). This effect is characterized by the negative adiabatic temperature change $\Delta {T}_S$ of an antiferromagnetic material when submitted to an applied magnetic field. In an isothermal process, a positive entropy change $\Delta {S}_T$ is also expected. More recently, the anisotropic character
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Memory and Communication-in-Logic Using Vortex and Precessional Oscillations in a Magnetic Tunnel Junction IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-11-24 Sonal Shreya, Milad Zamani, Yaseer Rezaeiyan, Hamdam Ghanatian, Tim Böhnert, Alex S. Jenkins, Ricardo Ferreira, Hooman Farkhani, Farshad Moradi
Wearable and implantable devices (WIDs) come with several separate blocks such as preprocessing units, memory, and data transmission blocks. Hence, in this letter, we present the concept of memory and communication-in-logic (MCL) using a magnetic tunnel junction (MTJ). Here, MTJ is presented as a memory device as well as an oscillator for communication purposes. Vortex-based spin-torque nanooscillators
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Effect of Buffer and Cap Layer on Thermally Stable Perpendicular Magnetic Anisotropy in Buffer/CoFeB/MgO/Cap Structure IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-11-09 Wei Du, Mengli Liu, Fengxuan Han, Hua Su, Bo Liu, Hao Meng, Xiaoli Tang
In this letter, we study the effect of buffer and cap layers on thermally stable perpendicular magnetic anisotropy (PMA) in a buffer/CoFeB/MgO/cap structure. Not only is the buffer layer crucial, but the type of cap layer also affects the thermal stability of PMA. Relative to the Ta samples, the W samples that adopt a W buffer or cap layer acquire a wider PMA thickness range for further increasing
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Iterative Multihead Multitrack Detection Scheme for Bit-Patterned Media Recording IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-11-03 Gyuyeol Kong, Taehyoung Kim, Minchae Jung
An iterative multihead multitrack detection scheme for bit-patterned media recording is described in this letter. The scheme employs two iterative strategies with multihead, multitrack detection where three tracks are simultaneously processed to accurately estimate the channel with track misregistration (TMR) and effectively detect the data by using intertrack interference ( ITI ) information with
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Experimental Demonstration of a Spin-Wave Lens Designed With Machine Learning IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-09-26 Martina Kiechle, Levente Maucha, Valentin Ahrens, Carsten Dubs, Wolfgang Porod, Gyorgy Csaba, Markus Becherer, Adam Papp
In this letter, we present the design and experimental realization of a device that acts like a spin-wave lens i.e., it focuses spin waves to a specified location. The structure of the lens does not resemble any conventional lens design. It is a nonintuitive pattern produced by a machine-learning algorithm. As a spin-wave design tool, we used our custom micromagnetic solver SpinTorch, which has built-in
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Novel Magnetic Localization Methods for Minimizing the Ellipse Error Based on Tensor Invariants IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-09-12 Xiangang Li, Shenggang Yan, Jianguo Liu, Youyu Yan
There are various technology routes for the localization of magnetic targets. Among them, localization methods based on magnetic gradient tensor invariants have remarkable preponderance. For instance, such invariants are not sensitive to the jitter of the coordinate system, which means this kind of method can be very suitable for application in moving carriers. The traditional classic method contains
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Robustness of Binary Stochastic Neurons Implemented With Low Barrier Nanomagnets Made of Dilute Magnetic Semiconductors IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-08-26 Rahnuma Rahman, Supriyo Bandyopadhyay
Binary stochastic neurons (BSNs) are excellent hardware accelerators for machine learning. A popular platform for implementing them is low- or zero-energy barrier nanomagnets possessing in-plane magnetic anisotropy (e.g., circular disks or quasi-elliptical disks with very small eccentricity). Unfortunately, small geometric variations in the lateral shapes of such nanomagnets can produce large changes
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Theoretical Circuit Design of an Efficient Spintronic Random Number Generator With an Internal Postprocessing Unit IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-08-19 Saeed Mehri, Abdolah Amirany, Mohammad Hossein Moaiyeri, Kian Jafari
In this letter, a spintronic true random number generator (TRNG) is designed using the stochastic switching feature of the magnetic tunnel junction device in the subcritical current regime. The proposed structure consumes low power and occupies a small area. Also, to improve the quality of random numbers production and compensate for the impact of process variations on the quality of the random output
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Safety Assessment of H-Coil for Nursing Staff in Deep Transcranial Magnetic Stimulation IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-08-16 Mai Lu, Shoogo Ueno
This work investigates the exposure experienced by the nursing staff executing deep transcranial magnetic stimulations (TMS) using H-coil. The safety assessment was implemented by employing the H-coil and realistic human model. The 144 relative positions of the H-coil with respect to the TMS operator body were considered, including the distance and vertical height. Dependence of the magnetic flux density
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Longitudinal Transformation of Magnetic Properties in Magnetic Microwires With Graded Magnetic Anisotropy IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-08-16 Alexander Chizhik, Paula Corte-León, Valentina Zhukova, Julian Gonzalez, Arcady Zhukov
We studied the magneto-optical and magnetic behavior of Co- and Fe-rich microwires that were stress-annealed at temperatures distributed along the microwire length. There was a transformation of the magnetic structure across zones subjected to annealing at different temperatures. Differences in the magnetic behavior between the surface and bulk were observed for both Co- and Fe-rich microwires. The
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Simulation of Magnetic Resonance Sounding With a Delayed Adiabatic Pulse IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-08-04 Benquan Yang, Yujing Yang
Magnetic resonance sounding (MRS) is used to identify groundwater by exciting and measuring the nuclear magnetic resonance of hydrogen nuclei in subsurface aquifers. However, the MRS response is particularly weak and has a low signal-to-noise ratio (SNR); therefore, signal enhancement methods, such as adiabatic pulses, are essential for MRS applications with strong interference. The key challenges
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Two Modes of Drag Reduction for Magnetorheological Fluids IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-07-26 Jing Cheng Lv, Ming Yu Wu, Tong Zhao, Yin Tao Wei
Magnetorheological fluids (MRFs) show a millisecond-level reversible response controlled by an external magnetic field and are, thus, widely used in many areas, especially vehicle dampers, clutches, and brakes. However, in the standby state, the piston or rotor of these devices still moves in the MRF and generates damping force or torque, which will deteriorate the performance and even significantly
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Construction of Energy Loops Using Magnetic Barkhausen Noise IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-07-15 Xiaoge Meng, Lin Li, Yanzhao Hou
Magnetic Barkhausen noise (MBN), which contains microstructure information of materials, is widely used in nondestructive testing (NDT) of magnetic materials. MBN energy (MBN energy ) is a time-independent indicator for NDT, but the initial MBN energy has no clear physical meaning and cannot be used to explain the relationship to the hysteresis loop. In this letter, based on the physical mechanism
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Development of a Temperature Sensor Using Spin-Crossover Fe(pyrazine)[Pt(CN)4I] Nanoparticles IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-07-08 Yunji Eom, Keonmok Kim, Hyeon-Jun Lee, Sri Ramulu Torati, CheolGi Kim
Device miniaturization requires temperature sensors with high resolution and precise calibration for measurements at reduced scale. We developed an optical temperature sensor using Fe2+ spin-crossover (SCO) material that has low and high spin states depending on temperature. We adjusted the operating range of the SCO (295–365 K) with an appropriate concentration of iodine. The color induced by temperature
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Normal Stress of a Micro–Nano Magnetorheological Elastomer IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-06-17 Xuhui Liu, Jinghu Wang, Huina Hu, Ziyun Fang, Bin Xu, Yan Wu, Lei Gao, Meiling Pu
A micro–nano magnetorheological elastomer (MRE) containing Fe3O4 nanoparticles was prepared, and its mechanical properties were analyzed. A microscopic static force model was used for MREs with different concentrations of nanomagnetic particles. To investigate the mechanical properties, an experimental platform was built, and its magnetic field flux was simulated with finite-element software. The results
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An Optimized Magnet Circuit Design to Reduce Power Consumption for Torsional Electromagnetic Actuators IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-06-16 Xian Shi, Guifu Ding
A torsional electromagnetic actuator that is actuated by the torque applied to a planar coil in an external magnetic field is designed, modeled, and analyzed in this letter. The analytical model of the magnetic torque is established. A magnet combination consisting of a rectangular magnet and a square-ring magnet magnetized in opposite directions is developed. A novel magnetic circuit is designed and
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Novel Radiation Hardened Magnetic Full Adder Using Spin-Orbit Torque for Multinode Upset IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-05-30 Alok Kumar Shukla, Arshid Nisar, Seema Dhull, Brajesh Kumar Kaushik
Spintronic-based integrated circuits have been extensively explored as viable contenders for space use since magnetic tunnel junctions (MTJs) are intrinsically immune to radiation effects. On the other hand, their complementary metal–oxide semiconductor (CMOS) peripheral circuitry is still susceptible to radiation-induced single-event upset (SEU) and multinode upset (MNU) caused by charge sharing.
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Synthesis of NdFeB Magnetic Particles With High (BH)max From Their Optimized Oxide Powders Through Reduction–Diffusion Method IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-05-30 Rambabu Kuchi, Vitalii Galkin, Seunghyun Kim, Jong-Ryul Jeong, Soon-jik Hong, Dongsoo Kim
Neodymium–iron–boron (NdFeB) magnetic particles with high (BH)max were obtained using optimized ball-milled (BM) NdFeB oxide powders, instead of unmilled NdFeB oxide powders, through combined chemical processes comprising the spray drying and reduction-diffusion (RD) methods. The NdFeB oxide particles were subjected to the BM process to control their structural properties, including shape and size
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A Technological Approach for Miniaturization of Three-Dimensional Inductive Levitation Microsuspensions IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-05-11 Emil R. Mamleyev, Achim Voigt, Ali Moazenzadeh, Jan G. Korvink, Manfred Kohl, Kirill Poletkin
In this letter, we report on a technological approach for miniaturization of a inductive levitating microsuspension based on nested three-dimensional (3-D) microcoil structures. In the developed approach, each 3-D microcoil is fabricated separately, beginning with the innermost and thus the smallest coil diameter of the nested microstructure. This helps to overcome fabrication restrictions due to the
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Logical and Physical Reversibility of Conservative Skyrmion Logic IEEE Magn. Lett. (IF 1.2) Pub Date : 2022-05-11 Xuan Hu, Benjamin W. Walker, Felipe García-Sánchez, Alexander J. Edwards, Peng Zhou, Jean Anne C. Incorvia, Alexandru Paler, Michael P. Frank, Joseph S. Friedman
Magnetic skyrmions are nanoscale whirls of magnetism that can be propagated with electrical currents. The repulsion between skyrmions inspires their use for reversible computing based on the elastic billiard ball collisions proposed for conservative logic in 1982. In this letter, we evaluate the logical and physical reversibility of this skyrmion logic paradigm, as well as the limitations that must