Magnetic Property Measurement System Research Articles

Changes in microstructure, magnetocaloric effect and critical behavior of La0.8Sr0.2MnO3 manganites by K/Co doping

We prepared La0.8-xKxSr0.2Mn0.95Co0.05O3 (0 ⩽ x ⩽ 0.1) (LKSMCO) through the modified sol-gel method (S-G) and its structure. Then, the magnetic, magnetocaloric, and critical behavior were analyzed. LKSMCO was confirmed to be the rhombohedral structure within the R-3c space group (No.167) using transmission electron microscopy and X-ray diffraction. For validating the chemical composition of LKSMCO, X-ray photoelectron spectroscopy and EDS were applied, showing that K+ was successfully doped. Phase transition of LKSMCO from paramagnetic to ferromagnetic phase near Curie temperature (Tc) was confirmed with a Magnetic Property Measurement System (MPMS). Using normalization and Banerjee's criterion, LKSMCO was demonstrated to be the second-order magnetic phase transition (SOMPT). As shown from the applied magnetic field, the maximal magnetic entropy (−ΔSMmax) of LKSMCO near Tc was 3.87 J/(kg K) (x= 0.00), 4.28 J/(kg K) (x= 0.05) and 4.44 J/(kg K) (x= 0.10). We employed the Kouvel-Fisher approach (KF) and modified Arrott plots to confirm the values of γ, δ, and β. This indicates that critical exponents of LKSMCO were consistent with the Mean-filed model.

Measurement of magnetic properties of grain-oriented electrical steel considering multi-physics factors influence

The magnetic properties of electrical steel sheets are strongly affected by the Multi-Physics Factors (MPF), such as bending stress, working temperature, and magnetization patterns. To investigate the complex magnetic properties of the material under MPF magnetizing conditions, a magnetic property measurement system is first developed, considering the effect of bending stress, temperature loading, and non-sinusoidal magnetization waveforms. Then, the magnetic and the loss properties of Grain-Oriented (GO) electrical steels under MPF magnetizing conditions are measured and discussed. Obtained results showed that bending stress and non-sinusoidal magnetization waveforms are positively correlated with the loss properties of electrical steel sheets, and elevated temperatures can mitigate the effects of bending stress and harmonics on magnetic properties and losses.

Eu/Ni doping on the structure, magnetocaloric effect and critical behaviour of La0.65Sr0.35MnO3 ceramics

Magnetic refrigeration (MR) technology possesses the potential to substitute conventional gas compression technology. It is necessary to find MR materials suitable for a variety of applications. In this study, La0.65Sr0.35-xEuxMn0.95Ni0.05O3 (x = 0.05, 0.075, 0.10) (LSExMNO) ceramics were prepared using a sol-gel synthesis process. The LSExMNO ceramics were confirmed to be the R‾3c space group (rhombohedral structure) by X-ray diffraction (XRD) analysis. The particles of LSExMNO ceramic particles were irregular polyhedral particles by Scanning electron microscopy (SEM). The chemical composition of LSExMNO was determined by energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The Magnetic Property Measurement System (MPMS) demonstrated that the LSExMNO ceramics display second-order magnetic phase transitions (SOMPT) around Curie temperature (TC). When the Eu3+ doping level increased, the Mn–O–Mn bond angle and length increased, weakening the exchange coupling of the Mn4+-O2--Mn3+ channel and decreasing the TC. As the amount of Eu3+ doping varied, the maximum magnetic entropy (–ΔSMMax) of the LSExMNO ceramics peaked at 4.03 J kg−1K−1 and cooling efficiency parameter (RCP) = 291.2 J kg−1 at x = 0.075. The Modified Arrott plots (MAP) and Kouvel-Fisher (K–F) approaches were applied for the purpose of certifying the critical exponents of LSE0.075MNO ceramics conform to the Mean Filed model. Compared with other magnetic materials, it displays an excellent magnetocaloric effect (MCE) with a TC of 299 K.

Evolution of Relaxor‐Type High‐k Dielectric in Bulk Pristine Cu2+ and Li+ Co‐Substituted Wurtzite ZnO

AbstractDielectric constants determine the level of miniaturization in capacitive components involved in electronic devices. Cu‐Li co‐doping is attempted to introduce the multiferroic relaxor nature of dielectricity and dilute magnetism in the bulk material simultaneously as Li+ ion substitution in ZnO lattice is known to form acceptor states within the band gap of ZnO and paramagnetic Cu2+ present in ZnO lattice can introduce dilute magnetism. Phase purity and substitution of Cu2+ and Li+ ions in ZnO lattice along with oxide‐ion vacancy formation was confirmed using Powder x‐ray diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive X‐ray analysis (EDX), X‐ray Photoelectron Spectroscopy (XPS), Inductively Coupled Plasma Mass Spectrometry (ICP‐MS) and Magnetic property measurement system (MPMS) studies. The dielectric constant (ϵr′) of bulk pristine Zn0.92Cu0.05Li0.03O and Zn0.9Cu0.05Li0.05O is found to be 18000 and 20000 respectively at 1000 Hz frequency at 600 °C. Both dielectric constant and dielectric loss were decreasing with increasing frequencies. The increase in dielectric constant (ϵr′) with increasing temperatures at different frequencies for Zn0.92Cu0.05Li0.03O1‐δ and Zn0.9Cu0.05Li0.05O1‐δ is likely due to the localized nature of hopping charge carriers in addition to interfacial polarization due to space charge. Tm was found to increase with increasing frequencies suggesting the relaxor nature of dielectricity in the Zn0.9Cu0.05Li0.05O1‐δ. Bulk pristine Zn0.9Cu0.05Li0.05O1‐δ also exhibits ferroelectricity at room temperature with remnant polarization Pr and Vc equal to 4.20e–02 μC/cm2 and 4.1e+03 V/cm at (30KV, 500 Hz) respectively. Zn0.9Cu0.05Li0.05O also shows the paramagnetic behaviour.

Diffusion of Alloying Cobalt Oxide (II, III) into Electrical Steel.

This paper aims to reduce power loss in electrical steel by improving its surface resistivity. The proposed approach involves introducing additional alloying elements through diffusion once the steel sheet reaches the desired thickness. Various effective techniques have been suggested and tested to enhance the resistivity of the strip. The method entails creating a paste by combining powdered diffusing elements with specific solutions, which are then applied to the steel's surface. After firing the sample, a successful transfer of certain elements to the steel surface is achieved. The amount and distribution of these elements can be controlled by adjusting the paste composition, modifying the firing parameters, and employing subsequent annealing procedures. This study specifically investigates the effectiveness of incorporating cobalt oxide (II, III) into non-oriented silicon iron to mitigate power loss. The experimental samples consist of non-oriented electrical steels with a composition of 2.4 wt% Si-Fe and dimensions of 0.305 mm × 300 mm × 30 mm. Power loss and permeability measurements are conducted using a single strip tester (SST) within a magnetic field range of 0.5 T to 1.7 T. These measurements are performed using an AC magnetic properties measurement system under controlled sinusoidal conditions at various frequencies. The research explores the impact of cobalt oxide (II, III) addition, observing successful diffusion into the steel through the utilization of a paste based on sodium silicate solution. This treatment results in a significant reduction in power loss in the non-oriented material, with power loss reductions of 14% at 400 Hz and 23% at 1 kHz attributed to the elimination of a porous layer containing a high concentration of the diffusing element. The formation of porosity in the cobalt addition was found to be particularly sensitive to firing temperature near the melting point. The diffusion process was examined through scanning electron microscopy (SEM) in combination with energy-dispersive X-ray spectroscopy (EDS). The results demonstrate improved power losses in the coated samples compared with the uncoated ones. In conclusion, this study establishes that the properties of non-oriented electrical steels can be enhanced through a safer process compared with the methods employed by previous researchers.

Controllable CVD Growth of 2D Cr5Te8 Nanosheets with Thickness-Dependent Magnetic Domains.

As a unique 2D magnetic material with self-intercalated structure, Cr5Te8 exhibits many intriguing magnetic properties. While its ferromagnetism of Cr5Te8 has been previously reported, the research on its magnetic domain remains unexplored. Herein, we have successfully fabricated 2D Cr5Te8 nanosheets with controlled thickness and lateral size by chemical vapor deposition (CVD). Then magnetic property measurement system revealed Cr5Te8 nanosheets exhibiting intense out-of-plane ferromagnetism with a Curie temperature (TC) of 176 K. Significantly, we reported for the first time two magnetic domains: magnetic bubbles and thickness-dependent maze-like magnetic domains in our Cr5Te8 nanosheets by cryogenic magnetic force microscopy (MFM). The domain width of the maze-like magnetic domains increases rapidly with decreasing sample thickness; meanwhile, the domain contrast decreases. This indicates the dominant role of ferromagnetism shifts from dipolar interactions to magnetic anisotropy. Our research not only establishes a pathway for the controllable growth of 2D magnetic materials but also points toward novel avenues for regulating magnetic phases and methodically tuning domain characteristics.

A Design of Automatic Magnetic Properties Measurement System for Under/Postgraduate Open Experimental Project: Effective, Low Cost, and Scalable

Contribution: This research designs an experimental education project of an automatic material magnetism properties measurement system. It explores how the do-it-yourself (DIY), hands-on establishment, and hardware–software integration experiment system could be leveraged to enhance the understanding of the electromagnetism theory and nonelectrical quantity measurement application. Background: Designing and establishing a prototype of an automatic measurement system are essential, inspiring and beneficial to comprehending and consolidating the theoretical principles and simulations in electromagnetism and nonelectrical quantity measurement technology courses. Furthermore, in the vision of batch deployment and flexible group teaching, a cost-efficiency, hard/soft integration system for the electromagnetism property measurement definitely fits the aim of innovation laboratory education. Intended Outcomes: This project is intended to guide the students to finish a comprehensive research-oriented project loop for multiple skills training. It is also intended to encourage student motivation and confidence through theory investigation, hands-on group collaboration, and tunning for performance calibration. Application Design: The design of the proposed project includes the literature review, hardware selection and assembly, system integration, software programming, interface visualization, and system performance calibration. The participants are assessed with both objective exam questions and subjective open survey for training objectives to reveal their increased knowledge, interests, skill confidence, and creative thinking. Findings: The proposed project has been used in 4-year laboratory open experiments with students at different levels from freshmen undergraduates to 1st-year postgraduates. A use case and survey assessment demonstrate tremendous knowledge, skills, and confidence improvement among students in electromagnetism and measurement technology courses.

Impact of manganese diffusion into non-oriented electrical steel on power loss and permeability at different temperatures

Minimising power losses and their consequences is a significant matter in electrical steel applications. Increasing the resistivity of the steel strips has been confirmed as a successful method to overcome the problem of power losses. To increase the resistivity of the strip, different effective methods have been proposed and tested. In this work, a new material has been proposed to achieve the objective of increasing the resistivity of the steel samples by adding Manganese (IV) oxide based on a diffusion technique. The surface of the samples is to be coated with the proposed Manganese oxide. This should guarantee an increase in the resistivity of the samples, which in turn reduces the power losses caused by the eddy current. The samples tested were of non-oriented electrical steels containing 2.4 wt% Si-Fe (with a thickness of 0.305 mm*300 mm*30 mm). It was measured for losses and permeability before and after treatment by a Single Strip Tester (SST) at 0.5–1.7 T using an Alternating Current magnetic properties measurement system under controlled sinusoidal at different frequencies. The obtained results revealed that the depth of Manganese oxide diffusion is inversely proportional to the increase in the temperature. It was demonstrated that the best amount of diffusion of the element into the strips was achieved at 525°C, which was 60 weight % in comparison with 700°C which was 20 wt%. Likewise, at 800°C it was 7 wt%. However, the depth of diffusion of the manganese was the same at those tested temperatures, which were equal to 200 µm deep on each of the side strips. The diffusion of the material was investigated using Scanning Electron Microscope (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS). Furthermore, from the results, it was concluded that the power losses in the coating samples were improved by 9% as compared with uncoated samples.

Magnetic solid-phase extraction based on GO/Fe3O4 coupled with UPLC-MS/MS for determining nitroimidazoles and their metabolites in honey

A magnetic graphene oxide (GO/Fe3O4) nanocomposite was synthesized in one step by a chemical coprecipitation method, which was further used for magnetic solid-phase extraction (MSPE). This study aimed to combine GO/Fe3O4 with ultra-high-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) to detect the nitroimidazoles (NDZs) and their three major metabolites in honey samples. GO/Fe3O4 was characterized by transmission electron microscopy (TEM), Fourier transform-infrared (FT-IR) spectroscopy, and magnetic property measurement system (MPMS), and the influencing parameters such as adsorbent amount, pH of the dissolved sample solution, sample volume, type and volume of the eluent, shaking speed, and adsorption and desorption time were optimized. Under the optimized conditions, the limits of detection (LOD) and quantitation (LOQ) of the method were 0.003–0.08 μg kg−1 and 0.009–0.3 μg kg−1, respectively, with good linearity reported in the range of 0.5–20 μg kg−1 (R2 ≥ 0.9991). The average recoveries of 10 analytes were in the range of 66.0%–90.8% with relative standard deviations (RSD) lower than 6.9% (n = 6). The preparation of GO/Fe3O4 and the extraction process were convenient and rapid, and consumed small amounts of organic solvents. The optimized method was successfully applied for extracting NDZs and their three major metabolites from honey samples with good accuracy.

The effect of thickness of niobium isolation layer on properties of copper-based Nb3Sn films

Copper-based Nb3Sn film is a promising material for applications in the field of superconducting radio frequency (SRF). However, the interdiffusion of copper (Cu) from the substrates into the Nb3Sn films affects the superconductivity of the samples, and the preparation of Nb3 Sn–Nb–Cu composite films is a good solution. In this paper, the effects of the niobium (Nb) layer thickness on Cu interdiffusion and the critical temperature of Nb3Sn film were investigated. Nb3 Sn–Nb films were deposited on Cu substrates by magnetron sputtering. The obtained samples have been characterized via focused ion beam (FIB), time of flight secondary ion mass spectrometry (TOF-SIMS), and magnetic property measurement system (MPMS). It was found that the thicker the Nb isolation layer, the stronger the hindrance effect on the Cu interdiffusion and the higher the critical temperature. A suitable Nb isolation layer thickness was 2.6μm, which effectively hindered the Cu interdiffusion, corresponding to a critical temperature of 16.6 K for the samples.

Study on preparation of Nb3Sn films by bronze route

As a promising material, in the field of superconducting radio frequency (SRF), Nb3Sn could be prepared via bronze route, which is fairly mature for preparing the superconducting cable. This paper studies how different annealing temperature and time affect the superconducting properties of Nb3Sn films made by bronze route. Niobium films with μm thickness were deposited on bronze substrates by magnetron sputtering. The prepared samples were annealed at 700 °C and 750 °C for several hours to allow the diffusion of Sn from the bronze substrate to the niobium layer and the formation of the Nb3Sn phase. The obtained films have been characterized via X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy analysis (EDS), and magnetic property measurement system (MPMS). The peaks of the Nb3Sn phase were found by XRD and the EDS result showed the Sn% of the cross-section fluctuates around 23at.%. The average crystallite size is estimated to be about 82 nm. The highest critical temperature of Nb3Sn films prepared by this method is up to 17.6 K.

Effect of Chlorine Addition on Texture and Superconducting Performance of YBa2Cu3O7−δ-Coated Conductors

YBa2Cu3O7−δ (YBCO) thin films with the addition of Cl were prepared on Hastelloy tape by the extremely low fluorine metal-organic deposition (MOD) technique. The composition and microstructure of the present samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was revealed that the Cl-added YBCO thin films achieved better texture and density compared with the pure YBCO films. The superconducting properties at magnetic fields were measured using the magnetic property measurement system (MPMS). The results showed that the sample onset transition temperature (Tc, on) did not change significantly after the addition of Cl. The critical current density (Jc) in the presence of YBCO with the addition of Cl increased significantly. Meanwhile, both the Jc and gravitational force (Fp) of the (Cl, Hf) co-added YBCO films were further enhanced at different magnetic fields. The thermodynamic analysis of the BaCO3 removal reaction revealed that the addition of Cl to YBCO formed chlorine compounds, which were effective in avoiding the formation of BaCO3. Further, the calculation results of the Gibbs free energy at different pressure quotients showed that the stability of the relevant chlorine compounds occurred in the order of BaCl2 > CuCl2 > YCl3 and the oxidation of BaCl2 to BaO required a higher temperature compared to BaF2, implying the potential advantages of inhibiting the a-axis growth.

Pressure-Induced Intermetallic Charge Transfer and Semiconductor-Metal Transition in Two-Dimensional AgRuO 3

Pressure-Induced Intermetallic Charge Transfer and Semiconductor-Metal Transition in Two-Dimensional AgRuO ₃

Analysis and experimental research on high frequency magnetic properties of different magnetostrictive materials under variable temperature conditions

Magnetostrictive materials have excellent magneto-mechanical properties and are widely used in the field of energy conversion. Temperature has an important influence on the magnetic properties of them. Accurately studying the temperature dependence of magnetostrictive materials is a necessary prerequisite for the design of precision actuators. In this paper, we constructed a high-frequency magnetic property measurement system that can control the temperature. The magnetic characteristics of Terfenol-D, Fe-Ga and Fe-Co were measured at temperatures ranging from 10 °C to 80 °C, the frequencies from 1 kHz to 20 kHz and magnetic induction amplitudes from 0.01 T to 0.07 T. The temperature dependence of the three materials under different exciting conditions was comprehensively compared. The variation trends and temperature sensitivities of the coercivity, permeability, equivalent inductance, equivalent resistance and the magnetic energy losses are analyzed respectively. The results of this paper are oriented to practical engineering applications and can be used for high-frequency loss prediction and temperature control system design.

Особенности в поведении температурных зависимостей магнитной восприимчивости кристаллов твердых растворов Bi-=SUB=-2-=/SUB=-Te-=SUB=-3-=/SUB=--Sb-=SUB=-2-=/SUB=-Te-=SUB=-3-=/SUB=-, содержащих от 25 до 70% теллурида сурьмы

The temperature dependences of the magnetic susceptibility of crystals of solid solutions of Bi2Te3-Sb2Te3 p – type conductivity containing from 25 to 70 mol. percent of antimony telluride obtained on a SQUID magnetometer MPMS (Magnetic Property Measurement System) MultiVu in the range from 2 to 400 K. A correlation was found between the features observed in the behavior of the temperature dependences of the magnetic susceptibility of crystals containing 60 and 70 mol. percent Sb2Te3 and the ratio of the plasmon energy to the gap energy between the chemical potential level and the heavy hole subzone. The assumption is formulated that in the case of convergence of these energies, the increasing electron-plasmon interaction affects the state of the electronic system, and thus the magnitude of magnetic susceptibility.

Synthesis of the Magnetically Nanoporous Organic Polymer Fe3O4@SiO2-NH2-COP and Its Application in the Determination of Sulfonamide Residues in Surface Water Surrounding a Cattle Farm.

Efficient extractions of trace antibiotic residues in the environment are a key factor for accurate quantification of the residues. A new nanoporous material, namely, magnetically covalent organic polymer (MCOP, Fe3O4@SiO2-NH2-COP) was synthesized in this work and was used for magnetic solid-phase extraction (MSPE). The combination of MSPE with high-performance liquid chromatography separation together with ultraviolet detection (HPLC-UV) was established as an effective method for the determination of four sulfonamide (SA) residues in surface water surrounding a cattle farm. The synthesized magnetic material was characterized by SEM, TEM, FT-IR, magnetic properties measurement system (MPMS), and nitrogen gas porosimetry. The material possessed many attractive features, such as a unique microporous structure, a larger specific surface area (137.93 m2·g−1) than bare Fe3O4 (24.84 m2·g−1), high saturation magnetization (50.5 emu·g−1), open adsorption sites, and high stability. The influencing parameters, including pH, the used amount of MCOPs, the type of eluent, adsorption solution, and desorption time, were optimized. Under the optimized conditions, the method conferred good linearity ranges (R2 ≥ 0.9990), low detection limits (S/N = 3, LOD, 0.10–0.25 μg·L−1), and satisfactory recoveries (79.7% to 92.2%). The enrichment factor (EF) for the four SAs was 34.13–38.86. The relative standard deviations of intraday (n = 5) and of interday (n = 3) were less than 4.8% and 8.9%, respectively. The equilibria between extraction and desorption for SAs could be reached within 150 s. The proposed method was sensitive and convenient for detecting SA residues in complex environmental matrices, and the successful application of the new MCOPs as an adsorbent was demonstrated.

A centrosymmetric Dy2 compound derived from acylhydrazone Schiff base ligand exhibiting zero-field single-molecule magnet behavior

Based on acylhydrazone Schiff base ligand (2,3′-Hpcad, N3-(2-pyridoyl)-3-pyridinecarboxamidrazone), a binuclear DyIII compound, [Dy2(2,3′-pcad)2(C6H5COO)4(H2O)2] (1), has been successfully prepared by the hydrothermal synthesis method, and fully characterized by single-crystal X-ray diffraction, elemental analysis, Raman spectra, diffuse reflectance spectroscopy and magnetic property measurement system. Compond 1 exhibits a centrosymmetric binuclear structure bridged by benzoate groups and each eight-coordinated DyIII ion is located in a slightly distorted biaugmented trigonal prism configuration (C2v-BTPR). In addition, alternating-current magnetic susceptibility measurements illustrate that 1 exhibits zero-field single-molecule magnet behavior with the higher effective energy barrier (Ueff) value of 114.0 K compared to other Dy2 compounds with C2v-BTPR configuration. In addition, this study reveals configuration of each DyIII ion and intra-molecular magnetic coupling of two DyIII ions may synergistically effect Dy2-SMMs properties. Furthermore, the band gap energy of 1 is found to be 2.65 eV, which proves 1 could be used as the wide-gap semiconductor.

Preparation and study magnetic properties of the nanosized ferrite Zn0.5Mn0.5Fe1.95Mo0.02Tb0.01Sm0.01Gd0.01O4 with negative magnetization. A new result

ABSTRACT This work, concern the studies of the local atomic structure of the rare-earth doped Zn-Mn ferrite (Zn0.5Mn0.5Fe1.95Mo0.02Tb0.01Sm0.01Gd0.01O4), characterization techniques such as thermogravimetric analysis, X-ray diffraction (XRD), and Magnetic Properties Measurement System (MPMS), allowed us the effect of rare earth and their impacts on the structure, the size of nanocrystals, and the magnetic properties of the formed nano-ferrite. The XRD analysis showed that a single-phase was obtained at a low temperature of 500°C, with an environmentally friendly process, and nanometric size (8 nm). Magnetic measurements show a superparamagnetic behavior at 80 and 300 K and a week ferrimagnetism at 5 K. Furthermore, these measurements showed that this sample exhibits negative magnetization under zero-field cooled measurements (ZFC) with a low applied field (100 Oe), while the magnetization remains positive under field-cooled (FC) measurement conditions for the same applied field, which is a new result never observed in the case of Zn-Mn doped nano-ferrite.

Effect of Ta irradiation on microstructure and current carrying properties of YBCO coated conductors with element doping

In the present work, we study the change of microstructural and current carrying properties of the YBa2Cu3O7−δ (YBCO) coated conductors (CCs) doped with mixed elements of Ta, Zr, Hf, Mn, and Sn after the irradiation of 1.9 GeV Ta ions. Magnetic property measurement system measurement was applied to study the current carrying properties of the irradiated YBCO CCs. The critical transition temperature (Tc, on) decreases by 0.5 K as the ion fluence reaches 5.0 × 1010 ions/cm2. It is revealed that for the irradiated samples with the fluence higher than 1.0 × 108 ions/cm2, their negative magnetization is enhanced pronouncedly as the applied temperature is lower than Tc, on, which implies that there are more antimagnetic phases being resistant to magnetic fields in these irradiated samples. Besides, the critical current density (Jc) and the pinning force (Fp) increase with the increase of the Ta ion fluence. Particularly for the case of the fluence more than 5.0 × 1010 ions/cm2, Jc reached 8.74 × 106 A/cm2 at 1 T and 30 K and Fp reached 8.84 × 1010 N/m3 at 1 T and 30 K. As a consequence, the Jc value of the studied YBCO CCs is improved by 4.4 times at 1 T and 30 K compared with the value of 1.98 × 106 A/cm2 of the primitive sample. Moreover, the sectional microstructures of the YBCO superconducting layer observed by a field emission transmission electron microscope show the columnar defects with the size of about 9 nm form in the doped YBCO films after the irradiation, confirming traces of continuous latent tracks exist as the evidence of effective mixed-pinning landscapes.

Soft magnetic properties of FeSiAl/carbonyl iron composites with high magnetic permeability and low magnetic loss

FeSiAl/carbonyl iron composites with high magnetic permeability and low magnetic loss was prepared. The microstructure and magnetic properties of the sample were studied by using XRD, SEM, EDS, XPS and superconducting quantum interference device (SQUID Quantum Design MPMS-3) magnetic property measurement system. It is found that with increase of carbonyl iron content, magnetic permeability of the composites increased, and magnetic loss first decreased and then increased. This manifestation may be produced by a competitive mechanism: the presence of carbonyl iron particles strengthens the magnetic coupling among FeSiAl particles, which leads to an increase in magnetic permeability and reduces hysteresis loss; on the other hand, the hysteresis loss of carbonyl iron itself is greater than that of FeSiAl. The composite has the lowest magnetic loss and highest magnetic permeability when the carbonyl iron content is 4%, which may have commercial application value in high-power electrical systems.