Development Of Magnetic Technology Research Articles

Field-free magnetic switching dependence on lateral interfaces in synthetic antiferromagnets by ion implantation

Field-free spin–orbit torque switching in synthetic antiferromagnets (SAF) holds significant promise for high-density spintronic memory and logic devices. In this paper, we realize the field-free magnetization switching in SAFs due to the local ion implantation-induced 45° lateral interface and symmetry breaking. Moreover, the magnetization switching ratio is enlarged by the lateral interface owing to the superimposition of a damping-like effective field and a symmetry-breaking effective field. Our work is significant for the development of magnetic random-access memory technology with high-speed and anti-interference ability.

Hybrid Method for Reducing the Residual Field in the Magnetic Shielding Room

This study proposes a hybrid method for improving the magnetic shielding performance of a magnetic shielding room (MSR) with few permalloy layers. In this method, two types of compensating coils are combined, one placed outside the MSR and the other placed inside. The coupling effect between the outside coil and the permalloy layer is used to adjust the residual field distribution characteristics of the MSR, and the inside coil is used to compensate for the adjusted residual field. This method has been verified with an MSR with two permalloy layers and an inner space of 1.3 m × 1.3 m × 2.2 m. According to the result, the residual field was reduced to less than 2.5 nT in a cube with a 0.4-m side length, which is seven times lower than that without compensation, and the inner space utilization rate was also improved by two times compared with existing MSRs with a comparable space size. The proposed method is of great significance in the development of magnetic shielding technology.

Development of a Hybrid Fixed-Wing UAV Aeromagnetic Survey System and an Application Study in Chating Deposit

In recent years, the development of airborne magnetic survey technology based on unmanned aerial vehicles (UAVs) has been rapidly advancing. The commonly used systems are the fixed-wing UAV-based, multi-rotors UAV-based, and unmanned helicopters-based magnetic survey systems. And, a type of hybrid UAV that uses a vertical takeoff and landing (VTOL) and fixed-wing cruise mode is increasingly being used to carry airborne magnetic survey systems. To meet the requirements of most UAVs for small-sized and lightweight payloads, a miniature magnetic survey system was developed and integrated into a hybrid fixed-wing UAV and formed an aeromagnetic survey system. And, a peripheral mineral exploration test was conducted in a known porphyry copper–gold deposit in southeastern China using the system. By processing the collected magnetic data with 3D inversion of susceptibilities, potential ore-bearing intrusive rocks were quickly identified and delineated, providing clues for peripheral mineral exploration in the mining area.

Assembly and Test Results of the RMM1a,b Magnet, a CERN Technology Demonstrator Towards Nb3Sn Ultimate Performance

As part of the High Field Magnet technology development carried out at CERN, demonstrators are under construction to explore the full potential of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn. The Racetrack Model Magnet (RMM) is one of them, building upon the successful Enhanced Racetrack Model Coil (eRMC) eRMC1a magnet which reached 16.5 T peak field or 16.3 T bore field at 1.9 K. The RMM1a,b magnet is composed of the same two previously tested eRMC racetrack-type coils and an additional middle RMM coil. This central racetrack-type coil features a closed cavity with a diameter of 50 mm and a total length of 526 mm. The coil pack is assembled in the same shell-based support structure as eRMC1a, using bladders and keys to allow for a precise control of the preload with minimal spring back and conductor overstress. The magnet was preloaded with a conservative approach limiting the equivalent peak stress in the coil blocks below 150 MPa. It was then successfully tested up to 16.7 T peak field or 16.5 T bore field at 1.9 K. This paper describes the assembly of the RMM1a,b magnet, relying on Finite Element Analysis (FEA) and mechanical instrumentation, as well as the powering test results at 4.2 K and 1.9 K.

Application of magnetic resonance imaging technology in the diagnosis of brain diseases

Every year, more than 20,000,000 patients were plagued by brain diseases worldwide. Brain diseases include stroke, brain tumors, alzheimer's disease，parkinson's disease and many other diseases. Common diagnostic methods include computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography, etc, and among these methods, MRI is the diagnostic method with the best safety, the highest detection rate and the best reproducibility. As an advanced imaging technique, MRI has the advantages of non-invasive, non-radioactive, multi-parameter imaging, which means MRI has an indelible role in diagnosing brain diseases. MRI can be divided into perfusion weighted imaging (PWI), diffusion weighted imaging (DWI) and functional magnetic resonance imaging (fMRI). This paper focuses on the technical principles, characteristics and clinical applications of these three methods, for the purpose of promoting the development of magnetic resonance technology and the advancement of clinical diagnosis and treatment of brain diseases.

Effects of moderate static magnetic fields on the lipogenesis and lipolysis in different genders of Caenorhabditis elegans

With the rapid development of magnetic technology, the biological effects of moderate static magnetic fields (SMFs) have attracted increasing research interest due to their potential medical diagnosis and treatment application. The present study explored the effects of moderate SMFs on the lipid metabolism of Caenorhabditis elegans (C. elegans) in different genders including male, female, and hermaphrodite. We found that the fat content was significantly decreased by moderate SMFs in wild-type N2 worms, which was associated with their development stages. The diameters of lipid droplets in N2 worms, him-5 worms, and fog-2 worms were greatly decreased by 19.23%, 15.38%, and 23.07% at young adult stage under 0.5 T SMF, respectively. The mRNA levels of lipolysis related genes atgl-1 and nhr-76 were significantly up-regulated by SMF exposure, while the mRNA levels of the lipogenesis related genes fat-6, fat-7, and sbp-1 were down-regulated by SMF, whereas the concentration of β-oxidase was increased. There was a slight effect of SMF on the mRNA levels of β-oxidation related genes. Moreover, the insulin and serotonin pathway were regulated by SMF, instead of the TOR pathway. In wild-type worms, we found that their lifespan was prolonged by exposure to 0.5 T SMF. Our data suggested that moderate SMFs could significantly modify the lipogenesis and lipolysis process in C. elegans in a gender and development stage-dependent manner, which could provide a novel insight into understanding the function of moderate SMFs in living organisms.

Study on the value of the prenatal-postnatal integrated management model in the screening, diagnosis, and treatment of fetal heart malformations.

With the development and widespread use of fetal ultrasound and magnetic resonance technology in recent years, approximately 75% of fetuses are diagnosed prenatally with congenital structural malformations, a serious birth defect that endangers the life and health of the newborn. In this study, we aimed to study and analyze the value of the prenatal-postnatal integrated management model in the screening, diagnosis and treatment of fetal heart malformations. All pregnant women who were to undergo delivery in our hospital between January 2018 and December 2021 were recruited as the first subjects in this study, and after excluding those who refused to participate in the study, a total of 3,238 cases were finally included as subjects of this study. All pregnant women were screened for fetal heart malformations using the prenatal-postnatal integrated management model. Maternal files were established for all cases of heart malformations, grading the fetuses according to their heart disease grade, observing and recording their deliveries, treatment results and follow-ups. After screening for heart malformations using the prenatal-postnatal integrated management model, 33 cases of heart malformations were identified, including 5 cases of Grade I (all delivered), 6 cases of Grade II (all delivered), 10 cases of Grade III (1 induced), and 12 cases of Grade IV (1 induced); 2 cases of ventricular septal defect healed spontaneously after delivery, and 18 infants were treated accordingly. The results of the later follow-up showed that 10 children had normalized their heart structure, 7 cases had slight alterations in the heart valves, and 1 case died. The prenatal-postnatal integrated management model is a multidisciplinary cooperation model with certain clinical value in the screening, diagnosis and treatment of fetal heart malformations, which is beneficial to comprehensively improve the ability of hospital physicians in the grading management of heart malformations, detecting fetal heart malformations early and predicting fetal changes after birth. It further reduces the incidence of serious birth defects, conforms to the development trend of the diagnosis and treatment of congenital heart diseases, enables to reduce child mortality with timely treatment, effectively improves the surgical prognosis of critical and complex congenital heart diseases, with a promising application prospect.

PID Control of Magnetic Levitation (Maglev) System

Magnetic levitation is a process of drifting or shifting an object with a certain reference, by creating a repulsive force from the gravity of an object caused by an electromagnetic field without noise. In modern times like today, with the density of community activities, especially those living in urban areas, it is necessary to be able to carry out activities efficiently as well as quickly. Therefore, the reason for many people to be able to find an innovative solution to make it easier for humans to carry out their activities. One of the innovations that can be a solution to the limited space and time is in the development of magnetic levitation technology. The system that will be used in controlling this maglev is to use a PID controller. Using this PID control will be tested with several , , and values with a setpoint of 950. At the initial tunning with the values =2, =0.01, and =2. Then in the second test using the values =3, =0.1, and =0.3. Software testing is also carried out using matlab. The exact PID value for controlling an elevated object can be found by changing the value of the , , and values that can be searched through a matlab software in the PID tunner feature, which can then be seen the PID tunning results by analyzing the graph that will be displayed by the PID tunner.

A Review of Magnetic Shielding Technology for Space Radiation

The space radiation environment outside the protection of the Earth’s magnetosphere is severe and difficult to shield against. The cumulative effective dose to astronauts on a typical Mars mission would likely introduce risk exceeding permissible limits for carcinogenesis without innovative strategies for radiation shielding. Damaging cardiovascular and central nervous system effects are also expected in these space environments. There are many potential options for advanced shielding and risk mitigation, but magnetic shielding using superconductors offers several distinct advantages including using the conditions in space to help maintain the superconductor’s critical temperature and lower mass compared to equivalent passive shielding materials. Despite these advantages, the development of magnetic shielding technology has remained primarily in conceptual stages since the introduction of the idea in 1961. Over the last several decades, magnetic shielding has experienced periods of high and low attention by the human spaceflight community, leading to computational tools with single-use or other limitations and a non-uniform distribution of publications on the topic over time. Within the context of technology development and the surrounding space policy environment, this paper reviews and summarizes the available literature on the application of active magnetic shielding for space radiation protection, identifies challenges, and highlights areas for future research.

Magnetization dynamics at finite temperature in CoFeB–MgO based MTJs

The discovery of magnetization switching via spin transfer torque (STT) in PMA-based MTJs has led to the development of next-generation magnetic memory technology with high operating speed, low power consumption and high scalability. In this work, we theoretically investigate the influence of finite size and temperature on the mechanism of magnetization switching in CoFeB–MgO based MTJ to get better understanding of STT-MRAM fundamentals and design. An atomistic model coupled with simultaneous solution of the spin accumulation is employed. The results reveal that the incoherent switching process in MTJ strongly depends on the system size and temperature. At 0 K, the coherent switching mode can only be observed in MTJs with the diameter less than 20 nm. However, at any finite temperature, incoherent magnetization switching is thermally excited. Furthermore, increasing temperature results in decreasing switching time of the magnetization. We conclude that temperature dependent properties and thermally driven reversal are important considerations for the design and development of advanced MRAM systems.

Production of motor-wheels for prototypes of mini-electric vehicles based on new soft magnetic materials

This article discusses the issue of production a motor-wheel for prototypes of mini-electric vehicles based on new soft magnetic materials. The structure and morphology of the surface obtained composite materials have studied. The density value calculated from the X-ray diffraction data is about 3% higher than the directly measured values, which are 7.7 g/cm3. Technologies and create new technical means and their effective use, the results of development and research of magnetic materials and complex technology for constructing electric motors based on them are disparate and do not allow the creation of new approaches for their mass implementation. Tests of the electromagnetic characteristics of magnetic circuits based on the materials obtained for constructing an electric drive were carried out using an express magnetometer.

A new method to enhance the magnetocaloric effect in (Sc,Ti)Fe2 via magnetic phase separation

Magnetic refrigeration based on the magnetocaloric effect (MCE) is a novel refrigeration technology that will replace traditional vapor-compression refrigeration in the future. Improvement in the performance of MCE materials is crucial for the development of magnetic refrigeration technology. This study presents a new method that enhances the MCE performance of (Sc,Ti)Fe2 via magnetic phase separation. The maximum magnetic entropy change induced by the coexistence of an in-plane ferromagnetic phase (FMab) and a canting antiferromagnetic phase (CAFM) in Sc0.3Ti0.7Fe2 is twice that found in other (Sc,Ti)Fe2 compounds. Variable-temperature neutron diffraction experiments directly reveal that the large magnetic entropy change in Sc0.3Ti0.7Fe2 is dominated by the transformation from a highly ordered FMab state to a CAFM state with a lower magnetic order. The magnetic phase separation is a direct transition from a higher-ordered state with a larger lattice to a lower-ordered state with a smaller lattice that induces a large magnetic order change and lattice contraction. The combination of the metamagnetic transition and negative thermal expansion leads to enhanced MCE. This study suggests the possibility that magnetic phase separation can be an effective approach to achieving and controlling a large MCE in magnetic materials.

Process-induced magnetic tunnel junction damage and its recovery for the development of spin–orbit torque magnetic random access memory

The generation of torques in heterostructures of heavy metals and ferromagnets (HM / FM) in spin–orbit torque magnetic random access memory (SOT-MRAM) makes them interesting for the development of magnetic memory technology. Currently, the emerging SOT-MRAM technology faces major challenges in etching based on current manufacturing tools. In that respect, we experimentally investigate the two different etching recipes (namely, CF-Etch, & NH-Etch) of the reactive ion etching (RIE) process on the performance of a Ta/CoFeB/MgO/Ta (hard mask) magnetic film stacks to develop the SOT-MRAM technology. The experimental results demonstrate that CF-Etch etches Ta very fast, and MgO etches very slowly. In contrast, NH-Etch etches those two materials at a comparable rate. Both etches are terminated before MgO is removed. Based on the experimental results, we found that the CF-Etch reduces the interfacial anisotropy of CoFeB/MgO films. Moreover, the CF-Etch also destroys the magnetic moment of CoFeB film, which further deteriorates after the annealing process. In contrast, the magnetic properties of the stack are only slightly affected when the NH-Etch recipe is used. We also discuss the advantages and disadvantages of these two recipes based on the experimental study. Finally, we developed the SOT-MRAM devices based on these two etching recipes of the RIE process to improve the etching yield of this technology. The current SOT-MRAM fabrication process enables a uniform etch stop on the thin tunnel barrier layer and the Ta heavy metal layer (HM). A wafer-level statistical study of SOT switching characteristics, including tunnel magnetoresistance (TMR), SOT switching thresholds, and parallel/antiparallel state resistances (RP/RAP), has been performed.

Magnetic Technologies and Green Solvents in Extraction and Separation of Bioactive Molecules Together with Biochemical Objects: Current Opportunities and Challenges

Currently, magnetic technology and green solvents are widely used in chemical engineering, environmental engineering and other fields as they are environmentally friendly, easy to operate and highly efficient. Moreover, a magnetic field has positive effect on many physicochemical processes. However, related new methods, materials, strategies and applications in separation science still need to be developed. In this review, a series of meaningful explorations of magnetic technologies for the separation of natural products and biologic objects, including magnetic ionic liquids and other magnetic solvents and fluids, magnetic nanoparticles and magnetic fields, and the development of magnetic separators were reviewed. Furthermore, the difficulties in the application and development of magnetic separation technology were discussed on the basis of comparison and data analysis, especially for the selection of magnetic materials and magnetic field sources. Finally, the progress in the development of magnetic separators was also elaborated for researchers, mainly including that of the new high-efficiency magnetic separator through multi-technology integration and the optimization of traditional magnetic separators, which help current techniques break through their bottleneck as a powerful driving force.

Multi-channel non-destructive testing of steel strip stress based on magneto-elastic effect

ABSTRACT Internal stress is an important factor that affects the quality of strip products. Most online detection methods for internal strip stress have been realised by contact sensors. However, contact sensors are expensive to manufacture and tend to scratch the strip surface. The purpose of this study was to develop a multi-channel non-contact stress detection system that can reflect the longitudinal stress inhomogeneity of the strip in the width direction. First, a finite element model of residual stress detection based on the magneto-elastic effect was established in COMSOL, and it was calculated that the detection sensitivity was optimal when the sensor was arranged at 45°. Magnetic shielding technology effectively reduces the minimum interference-free distance of the sensor. A prototype of the detection system was built, the accuracy of the simulation model and the feasibility of the online detection of common steel grades are proved by experiments. The simulation model can directly solve issues related to the sensor’s induced voltage and the minimum interference-free distance, thereby reducing the design cycle and trial production cost of the sensor and providing new ideas for the development of magnetic shielding technology. The experimental results demonstrated that the detection method was feasible, reliable, and displayed high detection precision.

Distributed Fiber Optic Sensing to Identify Locations of Resistive Transitions in REBCO Conductors and Magnets

High-temperature superconductors such as REBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7-x</sub> (REBCO, RE = rare earth) can generate strong magnetic fields that are promising for applications in particle accelerators and compact fusion reactors. Traditionally, voltage taps are installed in superconducting magnets to measure the voltage signals due to resistive transitions. The voltage-tap-based diagnostics is important for the development of magnet technology as it can help pinpoint the locations in the magnet windings that limit the magnet performance. The architecture of the multi-tape REBCO cable such as CORC wires, however, makes it difficult to apply the voltage-tap-based diagnostics to identify the locations of resistive transitions. Distributed fiber optic sensing (DFOS) has the potential to address this issue. In this paper, we report the measurements of thermal strain along a CORC wire based on optical frequency domain reflectometry with a maximum spatial resolution of 0.65 mm and a temporal resolution of 10 Hz. The optical fiber is co-wound with the CORC wire that is epoxy impregnated. During the test, current was increased until a resistive transition occurred in the conductor. The spectrum shift of the reflected light along the fiber was recorded. The results suggested that with proper thermal isolation from the cryogen, DFOS can be used to identify the locations of resistive transitions in CORC wires and magnets. The results will allow a better understanding of the causes of resistive transitions in REBCO conductors and magnets, which will help improve the REBCO magnet technology.

Multiphysics Numerical Simulation of the Transient Forming Mechanism of Magnetic Pulse Welding

Magnetic pulse welding (MPW) is widely used in the connection of dissimilar metals. The welding process involves the coupling of the electromagnetic field and structural field, which is a high-energy transient forming process. Based on the current experimental methods, it is difficult to capture the relevant data in the process of magnetic pulse welding, and the transient forming mechanism of magnetic pulse welding needs to be further studied. Taking the magnetic pulse welding of an Al-Mg sheet as an example, based on the Ansoft Maxwell and ANSYS finite element simulation platform, the loose coupling method was used to analyze an electromagnetic field generated by the discharging capacitor bank and structural field of the Al-Mg sheet under the action of electromagnetic force. The discharge period of the magnetic pulse welding capacitor bank was 62 μs. The current direction in the aluminum sheet changed once half a cycle, and the direction of the electromagnetic force was always consistent with the Z-axis. Under the skin effect, the magnetic induction intensity on the lower surface of the aluminum sheet was the largest. At 16 μs, the induced current, electromagnetic force and magnetic induction intensity in the aluminum sheet reached the peak values, which were 7.89 A/m2, 4.58 N/m3 and 12.6 T, respectively. The maximum electromagnetic force and velocity in the structural field were 2400 KN and 300 m/s. The structure field simulation reproduces the transient forming process of magnetic pulse welding, and clarifies the formation mechanism of the “intermediate zone rebound uncomposite zone-welding bonding zone-unbound zone”. Based on the numerical simulation technology, the research on the transient forming mechanism of magnetic pulse welding under multiphysics simulations can promote the development and application of magnetic pulse welding technology and better guide engineering practices.

Simulation and Experiment Analysis of Temperature Field of Magnetic Suspension Support Based on FBG.

Temperature rise is an important factor limiting the development of magnetic suspension support technology. Traditional temperature sensors such as thermocouples are complicated and vulnerable to electromagnetic interference due to their point contact temperature measurement methods. In this paper, the equivalent model of magnetic suspension support is established, and the temperature field is simulated and analyzed by magnetic thermal coupling calculation in ANSYS software. Then, a quasi-distributed temperature measurement system is designed, and the FBG temperature sensor is introduced to measure the temperature of the magnetic suspension support system by “one-line and multi-point”. By comparing the analysis experiments and simulations, the equivalent accuracy of the simulation model and the FBG temperature sensor can accurately measure the temperature of the magnetic suspension support.

A correlative study of iron metabolism based on q-Dixon MRI in benign prostatic hyperplasia and prostate cancer.

Clinical staging, Gleason score, and prostate-specific antigen (PSA) have been accepted as factors for evaluating the prognosis of prostate cancer (PCa). With the in-depth study of iron metabolism and the development of multiparametric magnetic resonance imaging technology, we used q-Dixon magnetic resonance imaging (MRI) to measure the iron content of the PCa patients' lesions, and used enzyme-linked immunosorbent assay (ELISA) to measure the iron metabolism indicators in the patients' serum samples, combined with the patients' postoperative clinical data for analysis. We found that the serum indexes were correlated with the T2 star values, International Society of Urological Pathology (ISUP) grade, and pathological classification in PCa patients (all P &lt; 0.001) but not in benign prostatic hyperplasia (BPH) patients (all P &gt; 0.05). The utilization of q-Dixon-based MRI and serum indexes allows the noninvasive measurement of iron content in prostate lesions and the assessment of differential iron metabolism between PCa and BPH, which may be helpful for evaluating the prognosis of PCa.

Magnetic and anisotropic magnetocaloric effects of HoCoSi fast quenching ribbons

The performance of magnetocaloric effect materials is one of the key factors restricting the development of magnetic refrigeration technology. Materials with anisotropic magnetocaloric effect can be used in the rotary magnetic refrigeration technology, which is beneficial to the simplification of refrigeration devices. In this work, the magnetic properties, magnetocaloric effects, and magnetic anisotropies of rapidly quenched HoCoSi compounds are investigated. At low temperatures below &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;t&lt;/sub&gt; = 5.7 K, the HoCoSi ferromagnetism and helical magnetism coexist. With the increase of temperature, the HoCoSi undergoes a second-order phase transition from ferromagnetic (FM) to paramagnetic (PM) phase at &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;C&lt;/sub&gt; = 13.7 K. Both XRD and SEM show that the HoCoSi has a preferred orientation. In order to obtain a large magnetocaloric effect and to determine the effect of preferred orientation on magnetism and magnetocaloric effect, the isothermal magnetization curves of the 10 m/s–HoCoSi fast quenched belt in the directions of &lt;i&gt;H&lt;/i&gt; parallel and perpendicular to texture around the Curie temperature are analyzed. The corresponding magnetic entropy change (–Δ&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;M&lt;/sub&gt;) and magnetic refrigeration capacity (RC) are calculated. Under the magnetic field changing from 0 to 5 T, the value of –Δ&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;M&lt;/sub&gt; is 22 J/(kg·K) in the direction of &lt;i&gt;H&lt;/i&gt; parallel to the texture and 12 J/(kg·K) in the direction of &lt;i&gt;H&lt;/i&gt; perpendicular to texture , and their corresponding values of RC(RCP)are 360 (393.8) J·kg&lt;sup&gt;–1&lt;/sup&gt; and 160 (254.4) J/kg. The value of –Δ&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;M&lt;/sub&gt; reaches 12.5 J/(kg·K)even at &lt;i&gt;μ&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;&lt;i&gt;H&lt;/i&gt; = 0–2 T in the direction of H parallel to the texture. It is obvious that the 10-m/s-HoCoSi fast quenching belt shows a large low-field magnetocaloric effect and obvious magnetic anisotropy, which is expected to be used to realize the magnetic refrigeration technology of rotating samples.