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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
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A 0.5-T pure-in-plane-field magnetizing holder for in-situ Lorentz microscopy
摘要： A side-entry specimen holder capable of applying a 0.5-tesla in-plane magnetic-induction field for in-situ transmission electron microscopy was developed. Three miniaturized electromagnets with 300 × 300-μm pole area and 180-μm pole gap are stacked along the electron-beam path in the holder. The middle magnet is used for magnetizing the specimen, which is inserted into the pole gap by using a 40-μm-width cantilever for atomic-force microscopy. The upper and lower magnets are used to keep the electron beam parallel to the optical axis. Magnetic-field magnitude was determined on the basis of experimentally measured electron-deflection angles and induction-field profiles along the electron-beam path calculated by finite element electromagnetic simulation. Magnetization reversal in 300-nm-thick Nd-Fe-B magnets from the saturated state was in-situ observed by using the holder and a 1-MeV cold-field-emission transmission electron microscope. The observation revealed that domain-wall pinning occurred in different manners at the c-plane and non-c-plane grain boundaries. The holder was thereby shown to be useful for analysis of magnetization-reversal behaviors of hard magnetic materials.
关键词： In situ transmission electron microscopy,Specimen holder,Magnetic domains,Finite element method,Lorentz microscopy,Hard magnetic material
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE International Magnetic Conference (INTERMAG) - Singapore (2018.4.23-2018.4.27)] 2018 IEEE International Magnetics Conference (INTERMAG) - Scaling of all-optical switching to nanometer dimensions
摘要： The paper discusses the magnetic properties and applications of nanoscale materials, focusing on their use in optoelectronics. It presents experimental results on the manipulation of magnetic domains and the effects of external fields on material behavior. The study highlights the potential for improved device performance in magnetic storage and sensing applications.
关键词： device performance,nanotechnology,optoelectronics,magnetic materials,magnetic domains
更新于2025-09-19 17:15:36