- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Morphology and magnetic properties of grain-oriented steel scribed using different picosecond lasers
摘要： Micro-scribing experiments were conducted to investigate the characteristics of the associated ablative behavior and the improvements to the magnetic properties of grain-oriented steel using both a 532 nm and a 1064 nm wavelength ultra-fast picosecond laser. Ablative morphological characteristic analysis and elemental analysis were carried out using a 3D confocal microscope, a scanning electron microscope, and energy-dispersive spectroscopy. The damage mechanisms were analyzed by comparing the ablation morphologies. Furthermore, an iron loss tester and magnetic domain observation instrument were used to analyze the dynamic hysteresis loop, macroscopic magnetic property parameters, and to observe the microscopic structure of the magnetic domains. The magnetization behavior, loop characteristics, and magnetic domain refinement mechanisms were discussed. The results indicated that the magnetic domains were clearly refined and that the magnetic properties were significantly improved after picosecond laser scribing of the grain-oriented steel. The sample scribed using an ultra-fast wavelength 532 nm laser was more effectively scribed: the magnetic domain was slightly more refined, the iron loss was reduced by 15.73%, the coercivity was reduced by 24.42%, the residual magnetism was reduced by 20.8%, and the relative permeability was increased by 10.3%. The surface was of a high quality, but there were traces of stress damage caused by high-pressure steam in the scribed area. The 1064 nm wavelength ultra-fast laser clearly showed the effects of heat accumulation in the scribed area. Defects due to thermal damage were more common. The improvement to the macroscopic magnetic properties depended largely on the surface quality of the scribing and the penetration depth of the residual stress in the sample.
关键词： Magnetic domains,Laser surface treatment,Scanning electron microscopy,Iron core loss,Magnetic properties,Grain-oriented silicon steel
更新于2025-09-23 15:21:01
-
: <i>Ab initio</i> and Monte Carlo approaches
摘要： The effects of nonmagnetic impurity doping on magnetic and ferroelectric properties of multiferroic delafossite CuCrO2 are investigated by means of density functional theory calculations and Monte Carlo simulations. Density functional theory calculations show that replacing up to 30% of Cr3+ ions by Ga3+ ones does not significantly affect the remaining Cr-Cr superexchange interactions. Monte Carlo simulations show that CuCr1?xGaxO2 preserves its magnetoelectric properties up to x ≈ 0.15 with a spiral ordering, while it becomes disordered at higher fractions. Antiferromagnetic transition shifts towards lower temperatures with increasing x and eventually disappears at x ≈ 0.2. Our simulations show that Ga3+ doping increases the Curie-Weiss temperature of CuCr1?xGaxO2, which agrees well with experimental observations. Moreover, our results show that the incommensurate ground-state configuration is destabilized by Ga3+ doping under zero applied field associated with an increase of frustration. Finally, coupling between noncollinear magnetic ordering and electric field is reported for x ≤ 0.15 through simulating P -E hysteresis loops, which leads to ferroelectricity in the extended inverse Dzyaloshinskii-Moriya model.
关键词： CuCrO2,multiferroic,Monte Carlo simulations,ferroelectric properties,magnetic properties,density functional theory,delafossite,Ga doping
更新于2025-09-23 15:21:01
-
Magneto-optical properties of Rare Earth metals substituted Co-Zn spinel nanoferrites
摘要： Cobalt–zinc ferrite nanoparticles (NPs) substituted with three different metals, Co0.5Zn0.5RexFe2-xO4 (RE = Ce, Dy, and Y; 0.00 ≤ x ≤ 0.05) were prepared hydrothermally. Fourier Transform-Infrared (FT-IR) Spectroscopy, X-ray powder diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDX) and Vibrating Sample Magnetometry (VSM) analyzed the products. The formation of cubic phase of spinel Co-Zn ferrite NPs were confirmed through XRD, FT-IR and FE-SEM techniques. The structural investigation of NPs by XRD revealed that the lattice parameter "a" decreases with the introduction of the RE in the ferrite structure by the substitution of Fe3+ by RE ions. The different magnetic parameters of Co0.5Zn0.5RexFe2-xO4 (RE = Ce, Dy, and Y; 0.00 ≤ x ≤ 0.05) NPs such as the saturation magnetization, coercivity, remanence, and magnetic moment were calculated and discussed in relation to structure and microstructure properties. M (H) hysteresis curves indicated that the samples exhibit superparamagnetic nature at room temperature. A slight improvement in the magnetization was obtained especially for the Ce- and Y-substituted Co0.5Zn0.5Fe2O4 (CZF) NPs at a certain RE level. However, the case Dy-substituted CZF products showed a sharp decrease in the magnetization with x > 0.01. The results are mostly ascribed to the substitution of smaller Fe3+ ions with larger RE3+ ions.
关键词： Spinel ferrites,Morphology,Rare earth substitution,Hydrothermal,Magnetic properties
更新于2025-09-23 15:21:01
-
Metal Filled Nanostructured Silicon With Respect to Magnetic and Optical Properties
摘要： Within this work the utilization of nanostructured silicon as host material with various magnetic nanostructures is reviewed whereas the magnetic and optical properties of the gained composite systems are elucidated. The metal filling of the pores is mainly performed by electroless deposition or by electrodeposition which is discussed by means of some examples. Furthermore, two different types of porous silicon (PSi) morphology are used for the deposition procedure. On the one hand microporous silicon offering luminescence in the visible range is utilized as template material. It offers a branched morphology with a structure size between 2 and 5 nm. In this case not only the magnetic response is investigated but also the influence of the metal filling on the optical properties. On the other hand mesoporous and macroporous silicon in it’s low pore regime is employed which offers straight pores with diameters up to 90 nm. In this case the magnetic response strongly depends on the size, the geometry and the spatial distribution of the metal deposits within the pores. A crucial role plays also the morphology of the porous silicon, especially the distance between adjacent pores which is an important parameter regarding magnetic interactions.
关键词： magnetic nanostructures,porous silicon,magnetic properties,electrodeposition,luminescence
更新于2025-09-23 15:19:57
-
Correlation between laser energetic parameters and magnetic properties of GO laminations under surface treatments with long, short or ultra-short pulsed lasers
摘要： Electromagnetic components mostly incorporate soft magnetic materials used as flux multipliers. Hence, any reduction in iron loss of the magnetic core yields in saving energy. Among the techniques, the local laser treatment is a non-contact method applied for 180° domain refinement (Patri et al. [1]). The present study reassessed the impact of laser treatment on the magnetic properties of grain oriented silicon steels. Various laser pulse widths are used: an ultra-short pulse laser mainly adapted to the ablation process and a long and short pulse durations used for both irradiation and scribing processes [2]. The power loss is measured with a Single Sheet Tester (150 × 150 mm2). Each type of treatment resulted in a power loss reduction of 15–35% at peak induction 1.5 T and frequency 50 Hz. However, only the scribing and the ablation improved also the apparent permeability. In this work, the laser energy parameters are used to estimate the laser impact on the heat affected zone, the groove depth, the induced thermal stress, and on the internal properties of a magnetic behavioral model: static permeability and dynamic magnetization property [3].
关键词： Groove depth,Heat affected zone,GO laminations,Induced thermal stress,Laser treatment,Magnetic properties
更新于2025-09-23 15:19:57
-
Emergence of two-magnon modes below spin-reorientation transition and phonon-magnon coupling in bulk BiFeO3: An infrared spectroscopic study
摘要： We have studied the low-temperature magnetic and infrared measurements on the BiFeO3 ceramic sample to investigate the behavior of phonons and magnon-phonon coupling below 300 K. From the magnetic study, we noticed two magnetic transitions near 150 and 257 K due to the spin-reorientation. Besides, this sample is found to be a mean-field system rather than a glassy system. In our assignment of the infrared modes, all the 13 allowed phonon modes are accounted for rhombohedral BiFeO3 at room temperature itself. Almost all the modes show anomalous behavior in their frequency dependence, close to the observed magnetic transitions. In addition, the emergence of two-magnon modes at 106 and 111 cm-1 below 160 K is observed due to a modification in the noncollinear spin structure. These results indicate the presence of magnon-phonon coupling in multiferroic BiFeO3 below room temperature.
关键词： infrared spectroscopy,Multiferroics,magnetic properties,magnon-phonon coupling
更新于2025-09-23 15:19:57
-
Preparation, structural and functional properties of PbTiO3-δ ceramics
摘要： In the present study, oxygen deficient PbTiO3-d ceramics were prepared by solid state-reaction method. The formation of the pure perovskite phase with tetragonal structure was confirmed for the 800°C/2h calcined sample by using X-ray diffraction analysis at room temperature. Energy dispersive X-ray spectroscopy analyses confirm the creation of oxygen vacancies in the system for charge compensations, as demonstrated by the percentage of O atoms of ~53%. The complex impedance data reveals important contributions of the oxygen vacancies to the total dielectric response that are homogeneous distributed within the sample. The room temperature magnetic properties show a weak ferromagnetic character in all the samples that might be attributed to the oxygen vacancies defects and to surface effects.
关键词： oxygen vacancies,EDX spectra,magnetic properties,ceramics,dielectric properties
更新于2025-09-19 17:15:36
-
Hybrid composite mats composed of amorphous carbon, zinc oxide nanorods and nickel zinc ferrite for tunable electromagnetic interference shielding
摘要： With the rapid growth of electronics and telecommunication industries, electromagnetic pollution is a serious concern to be addressed because it not only affects the sensitivity and performance of the devices but also affects human’s health. Here, we report lightweight hybrid composite mats, having porosity around 40%, composed of amorphous carbon, zinc oxide nanorods and nickel zinc ferrite for excellent electromagnetic interference (EMI) shielding in the X-band (8.2-12.4 GHz). The vibrating sample magnetometer measurement confirmed that the saturation magnetization value (Ms) of the composite materials enhances with the weight percentage of zinc oxide nanorods-nickel zinc ferrite (ZNF) powder, which leads to enhanced magnetic loss of the electromagnetic waves. With the thickness of 1.0 mm, the total EMI shielding effectiveness of the amorphous carbon composite was measured to be 25.70 dB which was further enhanced to 53 dB by the incorporation of the ZNF powder. Such high increment is attributed to the enhanced magnetic properties, interfacial polarization and dielectric properties of the composite. The synergistic combination of the materials results in the high reflection coefficient and absorption coefficient of the composites which were measured to be ~0.916 and ~0.083, respectively. Thus, the composites can shield up to 99.999% power of the electromagnetic waves which is shared by the 8.394% reflection and 91.605% absorption. Moreover, the magnetic, electrical and EMI shielding properties of the composites can be tuned by controlling the amount of ZNF powder in composites. Hence, the composite mats can be suitable for applications in defense and telecommunication.
关键词： A. Hybrid,A. Nano-structures,EMI shielding,B. Magnetic properties,B. Electrical properties
更新于2025-09-19 17:15:36
-
A series of two-dimensional lanthanide coordination polymers: synthesis, structures, magnetism and selective luminescence detection for heavy metal ions and toxic solvents
摘要： A series of two-dimensional lanthanide coordination polymers: synthesis, structures, magnetism and selective luminescence detection for heavy metal ions and toxic solvents
关键词： lanthanide ions,coordination polymers,luminescence properties,crystal structure,magnetic properties
更新于2025-09-19 17:15:36
-
Four Co( <scp>ii</scp> ) coordination polymers based on 4,4′-(1 <i>H</i> -1,2,4-triazol-1-yl)methylenebis(benzoic acid): syntheses, structural diversity, magnetic properties, dye adsorption and photocatalytic properties
摘要： Four Co(II) coordination polymers based on 4,4′-(1H-1,2,4-triazol-1-yl)methylenebis(benzoic acid) (H2tmlb), namely: {[Co4(tmlb)4(H2O)]·2CH3CN·4H2O}n (1), {[Co(tmlb)(bbibp)]·1.5CH3OH·2H2O}n (2), {[Co2(tmlb)2(bimmb)]·6CH3CH2OH·4H2O}n (3), and {[Co(tmlb)(bibp)(H2O)]·DMA}n (4) (bbibp = 4,4′-bis(benzoimidazo-1-yl)biphenyl, bimmb = 1,4-bis(imidazol-1-ylmethyl)benzene, bibp = 4,4′-bis(imidazolyl)biphenyl), have been synthesized under solvothermal conditions. Four Co complexes have been characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric (TG) analysis and powder X-ray diffraction (PXRD). The single-crystal X-ray diffraction analysis reveals that complex 1 shows a two-fold interpenetrating (3,6,6)-connected framework with a Schl?fli symbol of (4·62)2(42·610·83) topology; complex 2 shows a two-fold interpenetrating uninodal 4-connected cds topology with a point symbol of (65·8); complex 3 shows a 2D → 3D supramolecular structure through weak interactions; complex 4 shows a (3,4,6)-connected network with a point symbol of (4·62)2(42·64·93·106)(64·9·10) topology. Furthermore, the variable temperature magnetic susceptibilities of complexes 1–4 have been discussed. Complex 4 can selectively adsorb sulfate-containing dyes by Lewis acid–base interactions. And the four complexes all exhibit excellent photocatalytic capability in degradation of MB/MV.
关键词： Structural diversity,Coordination polymers,Photocatalytic properties,Metal–organic frameworks,Dye adsorption,Magnetic properties
更新于2025-09-19 17:15:36