Kai Lin Woon’s Post

In ferromagnetic materials, angular momentum of spins can be converted into mechanical rotation of the entire object through the effect called Einstein–de Haas effect. This can easily be explained by the presence of net magnetic moment in ferromagnetic object. However, on the contrary, this rotation also exists in antiferromagnetic materials with zero magnetic moment. These interactions between spin ordering and mechanics occur at picosecond timescales. It has been a mystery in these materials how spin ordering is coupled to such a macroscopic movement. Researchers from SLAC National Accelerator Laboratory, Argonne National Laboratory, University of California, Berkeley, Pacific Northwest National Laboratory, University of Washington, Stanford University, Massachusetts Institute of Technology, Brookhaven National Laboratory and Nanjing University have used ultrafast electron diffraction/microscopy (UED/UEM) to observe seesaw-like spin-driven reciprocal space rotation in FePX₃ (X = S, Se) 2D van-der-Waals thin films at nanoscale with 1 ps temporal resolution. This reciprocal space rotation translates to interlayer shear motion in real space. The findings unveil at nanoscale how the spins are related to the mechanical motion in antiferromagnetic materials at picosecond temporal resolution. This video demonstrates the UEM visualization of light-induced shear oscillations in FePS₃ above (right) and below (left) the Neél temperature acquired at 200 kV. The left panel shows white dashed curved lines indicating a Friedel pair of stationary bend contours corresponding to (0 6 0) and (0 -6 0) reflections. Read the excellent findings published in the journal Nature. https://lnkd.in/dXMi4Bh6 #spindrivenmotion #antiferromagnetism #UEM #UED #pumpprobe #electronmicroscopy

Our latest contribution to ejecta study in shock compression experiments has just been published in Journal of Applied Physics! This work significantly extends the analysis of ejecta in shock compression experiments by Photon Doppler Velocimetry (PDV) beyond single scattering. It establishes a comprehensive theoretical model that addresses the effects of multiple scattering, which is ubiquitous in many dynamical and disordered media, including ejecta. In particular, we present a rigorous derivation linking the usual PDV result representation and commonly used light transport models. Numerical simulations of this theoretical model emphasise the crucial role of multiple scattering and inhomogeneities in the particle density and size-velocity distribution. This result will certainly have a strong impact on the future of PDV-based ejecta analysis. This is the first article of my doctoral thesis prepared at Institut Langevin - Ondes et images and CEA, under the supervision of Jean-René Burie, Olivier Durand, Romain Pierrat and Rémi Carminati. I am happy to see the name of my engineering school, Institut d'Optique Graduate School, associated with it!

💌 Publications in journal Quantum Beam Science MDPI 🎓 Virtual Angstrom-Beam Electron Diffraction Analysis for Zr80Pt20 Metallic Glasses by Akihiko Hirata from Waseda University 🎁 This paper proposes a computational method for extracting the medium-range order from the models of amorphous structures constructed by a molecular dynamics (or reverse Monte Carlo) simulation through reciprocal space. Visit to download the full text: https://lnkd.in/dJS6c9Kb #electronbeam #diffraction #simulation #structureanalysis #glasses

#mathematics #openaccess 📢 Special Issue "Advances in Computational Electromagnetics and Its Applications" is open for submissions. Please contact estelle.wang@mdpi.com if you are interested in it. Finite Element Methods; Methods of Moments/Boundary Element Methods; Finite Difference Time Domain Methods; Finite Difference Frequency Domain Methods; High-frequency computational electromagnetic methods, such as multilevel fast physical optics methods and iterative physical optics methods; Discontinuous Galerkin Methods; Multi-physics coupling with electromagnetics; Acceleration techniques such as Fast Multipole Algorithms; Multiscale electromagnetic modelling; Combing artificial intelligence with computational electromagnetics; Electromagnetics in complex environments; Optimization and inverse problems in electromagnetics. https://lnkd.in/gaq-VPxW

Check out our latest blog regarding #metamaterials https://lnkd.in/eZfXPwbU, written by Nayan Kumar Paul, Ph.D., where we explore setting up simulations to excite hyperbolic waves in metal-dielectric layered #metamaterials, unlocking insights into their effective permittivity. Learn how these artificially crafted structures, with their anisotropic dispersion and customizable electrical properties, pave the way for groundbreaking applications—from superlensing to quantum engineering.

I stumbled upon a video covering a publication on magnetic fluid simulation. The initial calculation was computed using the volume and thus took considerable time to complete. However, a separate computation of the magnetic surface saved a lot of computing time and gave similar results of the magnetic behavior. This is the link: https://lnkd.in/gT9DaAWS #magnetics #simulations #computationaldesign #engineering #research

𝗗𝗶𝗱 𝘆𝗼𝘂 𝗸𝗻𝗼𝘄: 𝗗𝘆𝗻𝗮𝗺𝗶𝗰 𝗺𝗲𝗰𝗵𝗮𝗻𝗶𝗰𝗮𝗹 𝗮𝗻𝗮𝗹𝘆𝘀𝗶𝘀 𝗮𝘁 𝗮 𝗻𝗮𝗻𝗼𝘀𝗰𝗮𝗹𝗲 𝗶𝘀 𝗽𝗼𝘀𝘀𝗶𝗯𝗹𝗲 𝘄𝗶𝘁𝗵 𝗱𝘆𝗻𝗮𝗺𝗶𝗰 𝗻𝗮𝗻𝗼-𝗶𝗻𝗱𝗲𝗻𝘁𝗮𝘁𝗶𝗼𝗻 𝗺𝗲𝘁𝗵𝗼𝗱𝘀! 🗜️ Researchers and engineers interested in mechanical characterization are invited to join this month's #CovalentAcademy webinar exploring dynamic nano-indentation. Shivesh Sivakumar will give you an intro to the fundamentals of this technique before exploring some of the more advanced applications it unlocks on Covalent's UNHT3 platform from Anton Paar USA. #nanomechanical #mechanicalanalysis #nanoindentation Register now at: https://bit.ly/3VZCrcQ

SOLID STATE PHYSICS; LATTICE DYNAMICS; FCC CRYSTAL; MILLER INDICS; SCATTERING FACTORS FOR GATE AND CSIRNET #GATEMADEEASYKOTA, #CSIRNETMADEEASYKOTA, #PHYSICSMADEEASYKOTA, #NDAMADEEASYKOTA

"IMACS: Computational electromagnetics with ASERIS-BE™." A presentation by Benoît Chaigne from IMACS and Christos Liontas from BETA CAE Systems, for the 9th BEFORE REALITY Conference. Watch the video: https://lnkd.in/dS65jFzV #BeforeReality #physicsonscreen #engineeringsimulation

Spectral Proper Orthogonal Decomposition (SPOD) and Dynamic Mode Decomposition (DMD) are widely recognized for their ability to identify dominant flow and acoustic structures in various fields, including aeroacoustics. These methodologies, however, demand substantial data handling and involve complex linear algebra computations, which can be resource-intensive and time-consuming. To address these challenges, we have developed a new method that achieves comparable results to SPOD and DMD but with significantly reduced data handling requirements and simplified processing. This method leverages the cross spectrum technique to streamline the analysis process. In aeroacoustics, we demonstrated that our approach not only matches the capabilities of SPOD and DMD in identifying key structures but also provides additional insights that the traditional methods cannot. This innovative method has been published in the Aerospace Science and Technology journal (https://lnkd.in/dXxXEd-D). We hope that this offers a more efficient alternative for researchers, enabling them to conduct thorough analyses with less computational overhead and greater ease in aeroacoustics and beyond.