A method to optimize the topology of hard as well as soft magnetic structures is implemented using the density approach for topology optimization. The stray field computation is performed by a hybrid finite element-boundary element method. Utilizing the adjoint approach the gradients necessary to perform the optimization can be calculated very efficiently. We derive the gradients using a "first optimize then discretize" scheme. Within this scheme, the stray field operator is self-adjoint allowing to solve the adjoint equation by the same means as the stray field calculation. The capabilities of the method are showcased by optimizing the topology of hard as well as soft magnetic thin film structures and the results are verified by comparison with an analytical solution.
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http://dx.doi.org/10.1038/s41598-021-04246-z | DOI Listing |
Phys Chem Chem Phys
January 2025
Magnetic Resonance Center (CERM), University of Florence, via Luigi Sacconi 6, Sesto Fiorentino, 50019, Italy.
The function of biomolecular systems, including biological macromolecules, often crucially depends on their dynamics. Nuclear magnetic resonance (NMR) is one of the most informative methods used to study biomolecules and their internal mobility, with atomic resolution, in near-physiological conditions. NMR relaxation profiles, obtained from the field dependence of the nuclear relaxation rates, in particular, offer the possibility to probe dynamic processes over a wide range of time scales.
View Article and Find Full Text PDFMicromachines (Basel)
November 2024
School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo 454003, China.
Difficult-to-cut titanium matrix composites (TMCs) are widely used in the aerospace, automotive, and defense sectors due to their excellent physical properties. Electrochemical mill grinding (ECMG) can achieve the processing effects of electrochemical milling and electrochemical grinding using the same tool, which has the potential to complete the rough and finish machining of TMCs in succession. However, in the rough machining stage, the bottom of the slot becomes concave due to the inevitable stray corrosion, leading to poor flatness, which increases the machining allowance for subsequent finish machining.
View Article and Find Full Text PDFSci Rep
January 2025
Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093, Zurich, Switzerland.
We present a study on nanoscale skyrmionic spin textures in [Formula: see text], a rare-earth complex noncollinear ferromagnet. We confirm, using X-ray microscopy, that [Formula: see text] can host lattices of metastable skyrmion bubbles at room temperature in the absence of a magnetic field, after applying a suitable field cooling protocol. The skyrmion bubbles are robust against temperature changes from room temperature to 330 K.
View Article and Find Full Text PDFACS Nano
December 2024
SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea.
Half-metallic magnetism, characterized by metallic behavior in one spin direction and semiconducting or insulating behavior in the opposite spin direction, is an intriguing and highly useful physical property for advanced spintronics because it allows for the complete realization of 100% spin-polarized current. Particularly, half-metallic antiferromagnetism is recognized as an excellent candidate for the development of highly efficient spintronic devices due to its zero net magnetic moment combined with 100% spin polarization, which results in lower energy losses and eliminates stray magnetic fields compared to half-metallic ferromagnets. However, the synthesis and characterization of half-metallic antiferromagnets have not been reported until now as the theoretically proposed materials require a delicate and challenging approach to fabricate such complex compounds.
View Article and Find Full Text PDFSci Rep
December 2024
Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, Kolkata, 700064, India.
Antiferromagnetic materials offer potential for spintronic applications due to their resilience to magnetic field perturbations and lack of stray fields. Achieving exchange bias in these materials is crucial for certain applications; however, discovering such materials remains challenging due to their compensated spin structure. The quest for antiferromagnetic materials with exchange bias became a reality through our experimental study and theoretical simulation on and .
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