Magnetic Shielding Properties Research Articles

Impact of Air Gaps Between Microstrip Line and Magnetic Sheet on Near-Field Magnetic Shielding

This study experimentally analyzed the impact of air gaps between a magnetic sheet and a test board with a microstrip line, which is used to measure the near-field magnetic shielding effectiveness (NSE) of magnetic sheets made of metallic powder. To conduct the measurements, a material fixture equipped with a microstrip line to generate the near magnetic field, a rectangular loop probe, and an automatic probe positioning system capable of moving the loop probe along three axes were designed and fabricated. In addition, to systematically vary the thickness of the gaps, three paper spacers with a thickness of 0.11 mm per paper were used, and a 1.0 mm thick acrylic sheet, along with a specially designed material fixture, was used to press down the magnetic sheets during measurement. The magnetic shielding properties were measured and compared under various air gap conditions using a near-field magnetic loop probe. The effect of the gaps on the shielding performance of the magnetic sheets was quantitatively evaluated for three different magnetic sheets. The experimental results showed that as the gap thickness increased, NSE tended to improve up to a frequency around 1 GHz, while in the higher frequency range of a few GHz, NSE tended to decrease. The physical background of this phenomenon was explained using an equivalent magnetic circuit represented by reluctances for the structure, where the magnetic sheet is placed above the microstrip line with an air gap. This model helps to elucidate how the presence of the air gap affects the near-field magnetic shielding performance.

Optimization of structure, optical, magnetic, and radiation shielding properties of ZnO@xSrFe12O19 nanocomposites

In this work, the pristine ZnO, SrFe12O19 (SFO), and their nanocomposites (ZnO/x SFO: x = 1, 3 and 5%) were synthesized by co-precipitation and sonomechanical method. The x-ray diffraction data validate the preparation of ZnO, SFO, and nanocomposite samples with high phase purity. The optical band gap was calculated from UV–vis-NIR diffuse reflectance measurements, and it was modified by increasing SFO content. Adding 1, 3, and 5 wt% of SFO to the ZnO matrix showed ferromagnetic characteristics for the nanocomposites with a squareness ratio of around 0.49, which considered these nanocomposites as a magnetic semiconductor suitable for digital memory and spintronic applications. Additionally, the radiation shielding features of the prepared samples were evaluated. The shielding parameters for the studied samples were obtained using the Phy-X/PSD program. The fast neutron removal cross-section of SFO was 0.094 cm−1, the highest among the investigated samples, while the composites had similar values, about 0.083 cm−1. The results indicated that the γ--ray attenuation ability and the values of exposure buildup factor for the prepared samples were close. Therefore, ZnO, SFO, and their nanocomposites compared to stationary shielding materials (SMs), can be candidates for applications where radiation protection is needed.

Magnetic shielding properties of an iron-based nanocrystalline alloy for induction heating systems

A nanocrystalline alloy, with an iron-based composition (Fe58.5Si16.7B6.5Nb5.1Cu13.2) and a Curie temperature of 570 °C, was investigated for its effectiveness as magnetic shielding films in an induction heating system. The primary focus of the research was to evaluate the shielding performance of the 3-turned (9-layered) shielding films with dimensions of 135 mm × 17 mm × 0.15 mm. Upon winding, these films formed a cylindrical structure that enveloped the coil, with a diameter of 13.9 mm and a height of 17 mm. The results showed that increasing the degree of fragmentation within the nanocrystalline shielding films significantly reduced the magnetic permeability by decreasing the real component from 11,500 to 400 and the imaginary part from 2800 to 20. However, a lower degree of fragmentation led to a 10 % increase in the resistance (Rs) of the heating module, although this effect was less pronounced as the relative permeability continued to increase. Furthermore, observations on preheating time to a set temperature of 400 °C and total energy consumption over a duration of 250s revealed an initial downward trend, followed by a rapid increase that even exceeded the initial values as the magnetic permeability of the nanocrystalline shielding films augmented. Notably, the study emphasized that nanocrystalline shielding films with a relative permeability value of 1000 demonstrated exceptional magnetic shielding performance, resulting in a 12.5 % reduction in preheat time and 7 % less energy consumption during preheating. In addition to empirical findings, the study developed a theoretical model elucidating the shielding mechanism inherent in induction heating systems. This model serves as a robust framework for the application of nanocrystalline shielding materials in such systems, laying the groundwork for enhanced magnetic shielding capabilities in future applications.

Exploring the interplay of structure, optical, magnetic and radiation shielding properties in GeO2/Bismuth borate glasses

This article investigates the structural, chemical, optical, and magnetic properties of borate bismuth glasses doped with increasing GeO2 concentrations. X-ray diffraction (XRD), Raman spectroscopy, density measurements, thermal analysis, UV–Vis absorption, and VSM studied the impact of GeO2 on the glass network. The XRD results of the study confirmed that glass is amorphous. The bulk density increased while the molar volume decreased with increasing GeO2 concentration. Glass transition temperature (Tg) slightly decreases due to weaker Ge–O bonds and lower cross-linking density. Crystallization temperature (Tc) increased as GeO2 disrupts the network, hindering crystal nucleation and growth. Optical band gap narrows with increasing GeO2, with direct and indirect gaps decreasing. Urbach energy (EU) rises with GeO2, indicating increased disorder in the glass network. Refractive index (n) and extinction coefficient (k) both increased with GeO2, attributed to non-bridging oxygen formation. VSM measurements reveal an increase in saturation magnetization from 0.1 to 0.3 emu/g with increasing GeO2 content. Mass attenuation coefficient (MAC) and linear attenuation coefficient (LAC) investigations showed the efficiency of the glass system for radiation attenuation at varying energies. The unique properties of these borate bismuth glasses doped with GeO2 show promise for various technological advancements in optoelectronics and radiation shielding.

Study on the magnetic shielding properties of nanocrystalline strips under bending stress

The study of the magnetic properties of nanocrystalline materials under stress is of great significance for the construction of small and lightweight magnetic shielding rooms. Therefore, this paper investigates the effect of stress on the magnetic properties of nanocrystalline materials under the action of external bending stress. By comparing the test results of the soft magnetic measuring device with and without bending stress, it is found that the magnetic permeability (μ i) decreases by about 51.41% when the introduced bending stress σ is increased by about 5.96 × 107 pa, whereas the KuFe−Si (induced magnetic anisotropy constant) and Hk (field of magnetic anisotropy) increase by 5.30 × 102 J m–3 and 1.08 × 102 A m−1, respectively. The Jiles-Atherton (J-A) model considering the bending stress and radius of change correlation is established, and the typical parameters of the J-A model are fitted using the Gazelle Optimization Algorithm (GOA), and the RMSE (root mean square error) of all of them are less than 0.056 T. The magnetic domain density increased with the increase of bending stress, which verified the correlation between the J-A model parameters and the bending stress. Our results reveal that the nanocrystalline macroscopic and micromechanical magnetic properties can be effectively combined with the J-A model, which will provide a theoretical basis for the simulation study of the nanocrystalline magnetic shielding device in the actual stress situation.

Synthesis and Characterization of Zr4+-Y3+ Substituted Ba-Sr Hexaferrite Nanoparticles for Microwave Absorption and Electromagnetic Shielding Applications

Novel compositions of Ba0.5Sr0.5Fe12-1.1xZrxY0.1xO19 (0.0≤x≤0.5) nanoparticles were synthesized using sol-gel citrate precursor method. X-ray diffraction confirmed the formation of magneto-plumbite hexagonal phase with average crystallite size of 55-70 nm. The fourier transformed infrared spectroscopy revealed the presence of metal cations vibrational modes in 460-600 cm−1 range. The Zr-Y contents influenced magnetic behavior and shielding properties with maximum total shielding effectiveness of -31 dB in K band, and -21 dB in X-band, observed for x=0.35. The microwave absorption studies revealed optimum reflection losses with maximum value of -32 dB at 6.4 GHz frequency for x=0.35. The obtained values validate the candidacy of Zr-Y substituted Ba-Sr hexaferrite nanoparticles for uninterrupted airborne surveillance, radar absorption and high frequency shielding applications.

Crystal structure refinement, optical, magnetic, and X-band microwave shielding properties of Dy3+ doped Ni2Y-type strontium hexagonal ferrites

Ni2Y-type strontium hexaferrites having chemical dddof Sr1·8Ba0·2Ni2Fe12-xDyxO22 (x = 0.0, 0.1, 0.2) were made utilizing the sol-gel combustion technique. All samples' XRD patterns demonstrate the production of NiFe2O4 and Fe3O4 which are a phase that is intermediate in the synthesis of the required Ni2Y-type strontium hexaferrites. The FTIR indicates the presence of absorption peaks at about 557 and 432 cm−1, this shows the possibility of the formation of Y-type hexaferrites. UV-vis NIR spectroscopy analysis indicates that the energy band-gap of Y-type hexaferrites is affected by the increase in Dy3+ concentration. The values of the band-gap were found to be between 1.66 and 1.78 eV. According to the FESEM analysis, platelet-structure is formed with particles that range in size from 3.665 to 3.927 μm. The observed coercivity, saturation, and remnant magnetization first decreased with an increase in the concentration of Dy3+ for the sample having x = 0.1 and then increases for the sample with x = 0.2. The sample with the greatest amount of Dy3+ (i.e.x = 0.2) has a value of total shielding effectiveness of 27.5 dB. The prepared Ni2Y-type hexaferrites sample could be use for efficient shielding of microwaves in X-band.

FeCoNiMnCr high-entropy alloys (HEAs): Synthesis, structural, magnetic and nuclear radiation absorption properties

We report the synthesis and structural, magnetic and Radiation shielding properties of High Entropy Alloy (HEA) produced through mechanical alloying method. Using an X-Ray Diffractometer (PanalyticalEmpryan) with CuK radiation at 45 kV and 40 mA, the phase identification starting elements and as-milled powders are identified. Scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX), morphological and microstructural investigations were conducted (FEI Quanta FEG 450). EDX and elemental mapping analyses are conducted to assess the purity and elemental distributions of the synthesized alloys. Using the Quantum Design Physical Characteristics Measurement System (PPMS) with vibrating sample magnetometer (VSM) and a magnetic field of 30 kOe at room temperature, magnetic properties are examined. Using 137Cs radioisotope and mathematical methods, gamma-ray and neutron shielding properties of HEA are investigated in a conventional transmission setup using experimental and theoretical approaches. In the presence of a 3 T applied field, the sample exhibits a low magnetization of 5.30 emu/g at 300 K. Moreover, Ms is raised to 22 emu/g at 10 K owing to decreased thermal effects. The temperature dependence of the magnetization is recorded in the presence of a 1 T applied field. HEA exhibits superior neutron attenuation properties than conventional absorption materials such as B4C, graphite, and water. Our results showed that the synthesized HEA has superiority over other alloys and conventional neutron absorption materials. It can be concluded that the proposed novel HEA might be investigated further in terms of broadening its characterization and clarifying its other crucial properties to extend the scope of the current investigation.

Magnetic shielding up to 0.67 T at 77 K using a stack of high temperature superconducting tape annuli of 26 mm bore

In this work we demonstrate the magnetic shielding ability of a stack of YBa2Cu3O7 tape annuli. The annuli are cut from a 46 mm wide second generation coated conductor deposited on a Ni-5at.%W alloy ferromagnetic (FM) substrate. The inner bore of the stacked tapes is 26 mm and the outer diameter is 45 mm. Three samples with different height (24 mm, 14.9 mm, 9.9 mm) are studied. All the experiments are carried out at both room temperature and liquid nitrogen temperature (77 K). The shielding efficiency is investigated when the magnetic field is applied either parallel to the axis of the stack (axial shielding) or perpendicular to it (transverse shielding). Under an axial field, magnetic shielding is found to be effective (SF ) up to magnetic flux densities of 0.67 T. The presence of the FM substrates is found to have two important consequences. First, the stack of annuli is able to shield transverse flux densities in spite of its layered structure. Second, a finite magnetic shielding effectiveness is demonstrated at room temperature. In order to understand the contribution of the FM substrates to the shielding mechanism, we use the experimental field dependence of the magnetic permeability as determined independently from hysteresis loop measurements on the same substrates. A finite-element homogenized model solved with an H–φ formulation is shown to successfully reproduce the shielding factor of the stack at room temperature and 77 K, both under axial and transverse applied fields. These models are also used to assess the influence of the critical current density and the magnetic permeability on the shielding efficiency. Finally, the results are used to predict the magnetic shielding properties of higher stacks, demonstrating their significant potential to shield axial fields of T (with SF ) at 77 K.

Development of highly conductive hybrid Ni‐biocarbon‐based polyvinyl alcohol composites for microwave shielding properties

AbstractIn this study a highly flexible microwave shielding material was fabricated by solution casting method utilizing Nickel and biocarbon particles in PVA matrix and characterized for mechanical, magnetic, and microwave shielding properties. The main aim of this study was to prove the significant role of magnetic particles in electromagnetic interference (EMI) shielding along with conductive particles. The results show that the addition of Ni‐biocarbon hybrid particle increases the shielding properties up to 56.5 dB at 20 GHz. The magnetic permeability increased gradually with the inclusion of Ni particles with a highest magnetization, coercivity, and retentivity of 1250 E−6 emu, −9000 G, and 1100 E−6 emu. Similarly the mechanical results show that adding biocarbon enhances the composite's mechanical properties. A highest tensile strength, tear strength, elongation, and hardness are noted as 38, 168 MPa, 18.4%, and 36 Shore‐D. Comparatively, the hardness and elongation% of composite designations contains 3 and 5 vol% of hybrid particles have increased by 9% and 26%, respectively, in comparison to composite containing only 5 vol% of biocarbon with PVA. Scanning electron microscope fractography indicates biocarbon particles reduce voids and improve adhesion. These flexible EMI shielding composites could be used in telecommunication and other wave transmitting devices in engineering applications.

Effect of different aspect ratios of rectangular hole on magnetic shielding property for cylindrical shield

In this paper, the influence of rectangular holes with different aspect ratios in a cylinder on shielding properties is investigated using the finite element method. The two indicators used to assess the shielding properties of the cylinder are its internal residual magnetic field and its outer-surface magnetic field map. The internal residual magnetic field (B) of a cylinder as a function of the aspect ratio of a rectangular hole and its area is simulated, and the conclusions are as follows: with increasing length of the hole, the value of B increases first and then decreases. A cylindrical shield with square holes (the hole aspect ratio is equal to 1) delivers the worst shielding performance. A cylinder with a smaller hole area has better shielding properties, resulting from a less flux leakage from the environmental magnetic field. The anisotropy of the shielding properties is evaluated, and the magnetic shielding in the radial direction is better than that in the axial direction. This research provides a theoretical guide for the application and optimization of magnetic shields.

Pre-compliance testing of the shielding effectiveness of 3D printed multiwall carbon nanotube/ethylene-vinyl acetate copolymer composites in the 1 – 7 GHz range

Copolymer composites with 1-, 3- and 5 % weight concentration of carbon nanotubes (CNT) with average diameters of 9.5mm were fabricated using three different printing orientations: 0°, alternative ± 45°, and alternative +0°/- 90°. Shielding effectiveness (SE) of samples of 100x100x1 mm was measured with near-field probes connected to a vector network analyser based on a pre-compliance procedure. Both electric- and magnetic-shielding properties could be investigated. Using a reference material of a recognised producer, we emphasized comparative shielding properties in the (1-7) GHz range. Low SE values were generally observed for all samples, not exceeding 12.5 dB, but they were dependent on both the printing direction and CNT wt%. The measurements indicate that frequencies larger than 7 GHz may show better shielding properties. Also, indications of the best combination between CNT concentration and printing direction were deducted.

Study of a new axial-field superconducting inductor for a synchronous machine

In this work, a novel superconducting (SC) inductor topology for an axial flux synchronous machine is presented and tested. The proposed device combines HTS YBaCuO bulks and coils supplied with DC current to create a variable air gap flux density distribution. In fact, the two SC bulks modulate and redirect the flux lines produced by the coil thanks to their magnetic field shielding property. This results in a periodic space variation of the axial component of the flux density. A 3D electromagnetic modeling based on a finite element solution is developed to demonstrate the relevance of using the magnetic shielding properties of SC bulks. In order to verify the screening properties of the SC bulk, a prototype of the proposed inductor was constructed and tested in the laboratory.

High-Quality Ferromagnet Fe3GeTe2 for High-Efficiency Electromagnetic Wave Absorption and Shielding with Wideband Radar Cross Section Reduction.

A high-quality Fe3GeTe2 single crystal with good electrical, magnetic, and electromagnetic wave absorption and shielding properties was prepared in a large quantity (10 g level) by solid-phase sintering and recrystallization method, which would promote its in-depth research and practical application. It has good room-temperature electrical properties with a mobility of 42 cm2/V·s, a sheet (bulk) carrier concentration of +1.64 × 1018 /cm2 (+3.28 × 1020 /cm3), and a conductivity of 2196.35 S/cm. Also, a Curie temperature of 238 K indicates the high magnetic transition temperature and a paramagnetic Curie temperature of 301 K shows the large ferromagnetic-paramagnetic transition zone induced by the residual short-range ferromagnetic domains. Particularly, Fe3GeTe2 is in a loosely packed state when used as a loss agent; the electromagnetic wave absorption with a reflection loss of -34.7 dB at 3.66 GHz under thin thickness was shown. Meanwhile, the absorption band can be effectively regulated by varying the thickness. Moreover, Fe3GeTe2 in a close-packed state exhibits terahertz shielding values of 75.1 and 103.2 dB at very thin thicknesses of 70 and 380 μm, and the average shielding value is higher than 47 dB, covering the entire bandwidth from 0.1 to 3.0 THz. Furthermore, by using Fe3GeTe2 as a patch, the wideband radar cross-section can be effectively reduced by up to 33 dBsm. Resultantly, Fe3GeTe2 will be a promising candidate in the electromagnetic protection field.

Dielectric, magnetic and electromagnetic shielding properties of Poly-(3,4ethylenedioxythiophene)-maghnite associated with different fillers with any non-canonical shape

A new inverse measuring technique that corrects non-desired sample displacements and can handle any kind of sample shapes is presented. It is applied to the estimation of permittivity and permeability of Poly-(3,4ethylenedioxythiophene)-maghnite (PEDOT-Mag) associated with different additives such as iron, copper, and hydrogen. This electromagnetic characterization has been performed over the 9 to 11 GHz frequency range by comparing the simulated and measured scattering parameters of a partially filled WR-90 waveguide. Additionally, the reflection, absorption multiple reflection losses and the shielding effectiveness of these materials have been calculated. Results show higher values of dielectric constant and loss factor for PEDOT-Mag-copper, than those compounds associated with hydrogen or iron. As expected, the highest permeability values are achieved by PEDOT-Mag-iron. The composite PEDOT-Mag-copper exhibits higher attenuation constant, absorption loss, multiple reflection loss and shielding efficiency values than composites associated with iron or hydrogen. PEDOT-Mag-hydrogen, however, shows the highest reflection loss values.

Induced orientation of magnetic bentonite nanoparticles to produce low-density polyethylene nanocomposites

Clay-polymer nanocomposites have considerable importance in various areas of engineering; however, the addition of hydrophilic clays into hydrophobic polymer matrices is a challenge due to the low affinity between them, causing performance problems. Thus, the aim of this work was developing a method to improve dispersion and generate a high aligned morphology in clay-polymer nanocomposites. For this, clay nanoparticles with magnetic properties were produced and incorporated (3 wt% and 5 wt%) in low-density polyethylene matrices. The effect of the alignment on the thermal and thermo-mechanical properties of polymer was evaluated. The use of an external magnetic field during the molding process led to an efficient alignment of the nanoparticles, where the magnetic clay nanoparticles lined up along the magnetic field lines. The presence of nanoparticles had a crucial impact on the thermal properties of the nanocomposites with increments up to 40 °C in the initial degradation temperature of the polymeric matrix by forming physical barriers distributed across the samples. The alignment of nanoparticles also resulted in increments of up to 43% in the storage modulus of the polymer as a result of improved adsorption of mechanical energy. The results indicated a very promising methodology with potential application in the production of new polymeric materials with high barrier properties to liquids and gases and thin films with magnetic shielding properties.

Ta2O5 Nanocrystals Strengthened Mechanical, Magnetic, and Radiation Shielding Properties of Heavy Metal Oxide Glass.

In this study, for the first time, diamagnetic 5d0 Ta5+ ions and Ta2O5 nanocrystals were utilized to enhance the structural, mechanical, magnetic, and radiation shielding of heavy metal oxide glasses. Transparent Ta2O5 nanocrystal-doped heavy metal oxide glasses were obtained, and the embedded Ta2O5 nanocrystals had sizes ranging from 20 to 30 nm. The structural analysis of the Ta2O5 nanocrystal displays the transformation from hexagonal to orthorhombic Ta2O5. Structures of doped glasses were studied through X-ray diffraction and infrared and Raman spectra, which reveal that Ta2O5 exists in highly doped glass as TaO6 octahedral units, acting as a network modifier. Ta5+ ions strengthened the network connectivity of 1–5% Ta2O5-doped glasses, but Ta5+ acted as a network modifier in a 10% doped sample and changed the frame coordination units of the glass. All Ta2O5-doped glasses exhibited improved Vicker’s hardness, magnetization (9.53 × 10−6 emu/mol), and radiation shielding behaviors (RPE% = 96–98.8%, MAC = 32.012 cm2/g, MFP = 5.02 cm, HVL = 0.0035–3.322 cm, and Zeff = 30.5) due to the increase in density and polarizability of the Ta2O5 nanocrystals.

Coexistence of Zn and Fe ions influenced magnetic and microwave shielding properties of Zn-doped SrFe12O19 ferrites

We present the structural characterization, valence change of Fe, Raman spectra, and magnetic and microwave shielding properties of polycrystalline SrFe12-xZnxO19 (x = 0–1) samples. X-ray diffraction and Raman analyses indicated the samples having the M-type hexaferrite structure. The Zn doping caused a remarkable change in the lattice constants. Investigating magnetic hysteresis loops, we found an enhanced saturation magnetization (Ms) as increasing x from 0 to 0.1, and a reduced Ms as x > 0.1. Nearly the same tendency was also observed for the coercive force. Such changes have been thought to the Zn substitution and the valence change of Fe, as affirmed from analyzing the X-ray absorption data. Considering the shielding properties, we observed the samples with a thickness of 1.8 mm showing a low reflection loss. Among the investigated samples, the sample with x = 0.4 had the lowest reflection loss of about −20 dB at frequency of 11.7 GHz, corresponding to ~99% microwave energy being absorbed. We have considered that both dielectric and magnetic losses contribute to the microwave-absorption properties of SrFe12-xZnxO19.

Magnetically induced currents and aromaticity in ligand-stabilized Au and AuPt superatoms

Understanding magnetically induced currents (MICs) in aromatic or metallic nanostructures is crucial for interpreting local magnetic shielding and NMR data. Direct measurements of the induced currents have been successful only in a few planar molecules but their indirect effects are seen in NMR shifts of probe nuclei. Here, we have implemented a numerically efficient method to calculate gauge-including MICs in the formalism of auxiliary density functional theory. We analyze the currents in two experimentally synthesized gold-based, hydrogen-containing ligand-stabilized nanoclusters [HAu9(PPh3)8]2+ and [PtHAu8(PPh3)8]+. Both clusters have a similar octet configuration of Au(6s)-derived delocalized “superatomic” electrons. Surprisingly, Pt-doping in gold increases the diatropic response of the superatomic electrons to an external magnetic field and enhances the aromaticity of [PtHAu8(PPh3)8]+. This is manifested by a stronger shielding of the hydrogen proton in the metal core of the cluster as compared to [HAu9(PPh3)8]2+, causing a significant upfield shift in agreement with experimental proton NMR data measured for these two clusters. Our method allows the determination of local magnetic shielding properties for any component in large 3D nanostructures, opening the door for detailed interpretation of complex NMR spectra.

Magnetic shielding property for cylinder with circular, square, and equilateral triangle holes* *Project supported by the Key Projects of the National Natural Science Foundation of China (Grant No. 51535002) and the Programme of Introducing Talents of Discipline to Universities (Grant No. D17021).

The shielding property of cylinder with circular, square, and equilateral triangle holes was investigated by finite element analysis (FEA). The hole area (S hole) plays an important role in magnetic circuit on the surface of cylinder. When S hole is less than the critical area (S H), cylinder with three shapes of holes obtained the same remanent magnetization inside, indicating that the shielding property is unaffected by the shape of the hole. Hence, high-permeability material is the major path of the magnetic field. On the condition of S hole > S H, the sequence of the shielding property is equilateral triangle > square > circular, resulting from magnetoresistance of leakage flux in air dielectric. Besides, the anisotropy of shielding property caused by hole structural differences of the cylinder is evaluated. We find that a good shielding effectiveness is gained in the radial direction, compared with the axis direction. This research focuses on providing a theoretical support for the design of magnetic shield and improvement on the magnetic shielding ability.