Nanosurf’s Post

I am happy to share a 3-paper burst on the things I've been working lately.   2 of 3: “Structure and Dynamics of Magneto-Inertial, Differentially Rotating Laboratory Plasmas” (submitted to the Journal of Plasma Physics)   This paper extends our previous report on Physical Review Letters (https://lnkd.in/ewDRrTsT), with special emphasis on useful results for experimentalists. We provide a detailed characterization of the ablation dynamics, and jet structure and evolution. We found that the centrifugal barrier is sustained along the rotating jet which transports angular momentum. However, when a significant fraction of the mass of the load has imploded, the jet becomes kink unstable and gets disrupted.   By imaging the velocity field on an end-on image, we also show that difference in Doppler shift in Thomson scattering spectra can lead to wrong interpretations of the components of the velocity field if one incorrectly assumes that the probe passes through the axis.   We present calculations of the magnetic field configuration and ablation direction that allows the injection of angular momentum onto a rotating plasma column. These can be coupled to a self-similar solution describing the evolution of the plasma radius and rotation velocity, which should be independent for the driver. Thus, can be used to design versions this experiment on different drivers (pulsed-power or laser).   Preprint: https://lnkd.in/e9G2jaTQ

How does a liquid freeze? Amazingly this old question is not fully answered and this article pushes the experimental limit to measure it (used femtosecond 10^-15 sec X-ray diffraction)! On the more technical side, the results may help test and improve the theory of nucleation!

Happy to share our recently published article in Physical Review B on "Tunneling magnetoresistance in magnetic tunnel junctions with a single ferromagnetic electrode". Article highlights Normally, MTJs consist of two ferromagnetic (FM) electrodes separated by an insulating barrier layer. Their key functional property is tunneling magnetoresistance (TMR), which is a change in MTJ's resistance when magnetization of the two electrodes alters from parallel to antiparallel. Here, we demonstrate that TMR can occur in MTJs with a single FM electrode, provided that the counter electrode is an antiferromagnetic (AFM) metal that supports a spin-split band structure and/or a Néel spin current. Using quantum spin-transport calculation (DFT+NEGF), we predicted giant TMR effect of about 1000% in the (110)-oriented MTJs stems from spin-dependent conduction channels in Cr⁢O2 (110) and Ru⁢O2 (110), whose matching alters with Cr⁢O2 magnetization orientation, while TMR in the (001)-oriented MTJs originates from the Néel spin currents and different effective Ti⁢O2 barrier thickness for two magnetic sublattices that can be engineered by the alternating deposition of Ti⁢O2 and Cr⁢O2 monolayers. Our results demonstrate a possibility of a sizable TMR in MTJs with a single FM electrode and offer a practical test for using the antiferromagnet Ru⁢O2 in functional spintronic devices. Please take a look: https://lnkd.in/g3mBWtDw Phys. Rev. B 109, 174407 – Published 3 May 2024 #Phys. Rev. B #altermagnet RuO2 #DFT+NEGF

## Some exciting updates from our group at UR! In two back-to-back theory papers, we dive deep into the physics of quantum materials: 1️⃣ Published in Physical Review B: We uncover the role of nonlinearity and anisotropy in Rashba spin-orbit coupling within 2D Janus materials, revealing their impact on topological quantum properties and spin Hall conductivity. https://lnkd.in/eAqhUBF4 2️⃣ Published in Physical Review Materials: We explore a novel family of kagome metals, unveiling intriguing thermodynamic and vibrational properties, including flat phonons and some peculiar Einstein modes! https://lnkd.in/eNSDkTBX #QuantumMaterials #Spintronics #Kagome

🔬 Microscope Imaging of Battery Electrodes – Detecting Silicon! 🔍 At About:Energy we utilise a variety of physical and chemical analysis techniques on batteries, and one of my favourites is SEM + EDS! 📸 Scanning Electron Microscopy (SEM): We use SEM to image electrode particles with high precision, allowing us to quantify their size and structure. 💡 Energy Dispersive X-ray Spectroscopy (EDS): EDS is a powerful technique that detects elements within the electrodes. It identifies different transition metals in cathodes and detects silicon present in graphite. ⬇️ In the image below, you can see green silicon and red graphite highlighted in an LG electrode. 📚 We have captured hundreds of microscope images to build a comprehensive library of commercial batteries, providing a deep understanding of the latest battery technologies. By pairing this data with electrochemistry and other techniques, we can build a complete picture of the landscape.

This an interesting posting by Kieran O'Regan at About:Energy, showing the dispersion of silicon particles within a graphite electrode. Now, think about how carefully the silicon additive was mixed with the graphite anode material when LG prepared the slurry to apply on a large industrial electrode coating machine at high speed. Yet, as you can see visually, if you divide the picture into squares of 10 microns by 10 microns, some will have no silicon and others will have plenty. This means that the areal capacity (mAh per square) will vary quite a bit, owing to the much larger reversible capacity of the silicon and the variation in distribution. Now, imagine the cathode electrode area facing each square, and ask a simple question: if the average N/P ratio of the anode and cathode electrodes is 1.05, what is the actual N/P ratio variation from square to square? As you know, an N/P < 1.0 can create problems. But avoiding these problems (such as lithium plating) requires the local N/P ratios to vary less than 5% when comparing different areas across the electrodes. Remember than a single EV battery pack has several hundred square meters of separator = area of the interface between anode and cathode. When OneD Battery Sciences SINANODE process is applied to EV-grade graphite, the nano-silicon is fused into the pores of the graphite particles. Thus, the distribution of silicon within the graphite is at the particle level, before the slurry mixing…. In one of our 46XX cells, the electrodes are about 5 meters long… Uniform electrodes are key to performance, safety, and manufacturing yield (I.e. costs). Since EV batteries have much greater surface area than batteries in consumer electronics products, this is much more critical when selecting which silicon technology to use.

Recently I have read a few papers, but this one (by Uwe Bergmann et al.) is very much insightful! Using X- ray free- electron lasers for spectroscopy of molecular catalysts and metalloenzymes Simply speaking of it, it explains a great deal of information about the new method of X-ray spectroscopy, to use powerful x-ray sources to stimulate emissions of core-hole spectra of elements, so we can see what is happening through out a reaction in real-time. Since the emission occurs in a very short time (ultra fast or better say femtosecond), we can understand how each step of a reaction effects the electronic structure of a metal center, and therefore we can use this time synchronized spectra to gain an idea of how the reaction proceeds, And so to verify the reaction mechanism! It is too complex to explain in details, yet beautiful, so I guess you have to read it yourself :) #Xray #Spectroscopy #Chemistry #Reaction #Mechanism #Femtosecond #UltraFast and so many more tags :)

CT Physics -FRCR: https://lnkd.in/e-XJd5m5

CT Physics -FRCR: https://lnkd.in/e-XJd5m5

Pleased to share our latest research titled "Data-Driven Structure Recognition of Scanning Tunneling Microscopy Images in a Case of Iron Carbide," published in The Journal of Physical Chemistry Letters. This study presents a data-driven approach to streamline the identification of atomic structures from STM images, particularly on complex surfaces like iron carbides. By filtering through a structural database and matching with simulated STM images, we were able to narrow down potential surface structures, demonstrating the method with iron carbide on an Fe(110) crystal. For more details, you can read the full article here: https://lnkd.in/gvyZM6q9 #Research #PhysicalChemistry #STM #SurfaceScience #IronCarbide