Acta Materialia Inc. Family of Journnals’ Post

High harmonic spectroscopy retrieves electronic structure of high-pressure superconductors.

In our most recent article published in JACS, we track the cavity formation in electron solvation in water using x-ray spectroscopy and simulations https://lnkd.in/erx9Zz3d

F+++ me, this guy will eat me alive. Being a biologist who stumbled into more of a instumentation optimisation project for electron microscopy, I was decently afraid of giving my talk during EMC16 in Lyon in 2016. Back then I didn't really have a clue of what I was doing on my SEM. (Some say, it's like that to this day, though without a microscope) In spring 2016, I started reading papers from Mathieu Kociak and his team. Physicists only. A lab with a long history of knowing their sh++ in terms of spectroscopy with electrons. One piece I particularly enjoyed: https://lnkd.in/ecbcK_Jx (A collaborator (light microscopist) of us had developed a method where they'd count photons emitted from a sample, upion laser irradiation. They called it COPS (Counting On Photon Statistics) Being my true, unknowledgable biologist-self, I thought of adding their set up to my SEM , and do as Mathieu Kociak does. A contribution to our collaborator's group seminar later, that idea go discarded. Back to Lyon and EMC, though: Mustered up my courage, had a chat with Mathieu Kociak. Turns out, super nice guy. More than willing to help and answer my questions. #microscopymittwoch #science

DFT Calculations Predict Unexpectedly Bright and Chemically Tunable Fluorescent Quantum Defects in Boron Nitrides for Infrared Telecommunications and Biosensing https://lnkd.in/g9dbRTDa

Muon spectroscopy is an important experimental technique that scientists use to study the magnetic properties of materials. It is based on "implanting" a spin-polarized muon in the crystal and measuring how its behavior is affected by the surroundings.

Hexaferrites offer exciting potential for the next-generation high-frequency electromagnetic wave absorbents. While tuning their resonance frequency through chemical substitution is achievable, controlling reflection loss via spectral bandwidth remains a challenge 🚀. I’m thrilled to share our recent article, which showcases by means of micromagnetic simulations, that by structuring hexaferrite particles into hollow magnetic core-shell spheres, we can control the number and frequency of magnetic resonance modes. 🔍 What's New? For those who are not familiar with the subject, our findings demonstrate that by replacing the core of a ferrimagnetic hexaferrite particle by any other non-magnetic material, you can fine-tune its dynamic magnetic response, control the number of resonance peaks and adjust the spectral bandwidth for microwave applications ranging from 12 to 40 GHz. This is observed in particles with external diameters between 150 and 500 nm, producing additional resonance peaks comparable in amplitude to the main ferromagnetic mode of a solid sphere. 🤔 Why Are These Results Interesting? ▪ These properties are present at zero applied magnetic field, making them ideal for fabricating electromagnetic wave absorbents operating within the K band. ▪ Simulations indicate that spectral features can be tuned via magnetic shell size and thickness, both adjustable through conventional synthesis methods. ▪ These findings are robust against common experimental deviations from spherical geometry produced during material growth. 📈 What's Next? By publishing our theoretical findings, we aim to inspire the experimental fabrication of this innovative system. Read more about our article https://lnkd.in/erFz9jgv , and feel free to contact us with any questions. This work wouldn’t have been possible without the support of my supervisors. Special thanks to Christophe Lefevre, Daniel Stoeffler, and Nicolas Vukadinovic. #Hexaferrites #MicromagneticSimulations #ElectromagneticAbsorption #Nanoparticles #MaterialsScience #Core-shell 

Comparison of SPELEC RAMAN and standard Raman microscopes. Larger laser spot size can provide representative results with a single measurement. Standard Raman microscopes are traditionally used to perform Raman measurements or Raman spectroelectrochemical experiments when they are coupled with electrochemical equipment. Raman spectra collected with confocal microscopes allows the characterization of very small areas. However, these instruments can exhibit several limitations. SPELEC RAMAN, a new generation of spectroscopic and spectroelectrochemical instruments, offers powerful and interesting features to overcome these issues. In this Application Note, a detailed comparison is made between the main features of a standard Raman instrument and the SPELEC RAMAN by analyzing the results obtained with both instruments. https://lnkd.in/dncNPfEX

new preprint alert (corresponding author on this one!): here we used half-broadband two-dimensional electronic spectroscopy to investigate, with improved frequency and time resolution, the previously reported ultrafast symmetry-breaking charge separation (SB-CS) in the subphthalocyanine (SubPc) oxo-bridged homodimer. TD-DFT and cross-peaks reveal the dimer’s excitonic structure, whilst ultrafast spectral evolution unveils subtle features of structural relaxation, solvation dynamics and inhomogeneous broadening leading to the symmetry-broken state formation. Vibrational wavepackets reveal dimer specific low frequency Raman modes coupled to higher frequency vibrations localised on the SubPc cores. Finally, beatmap amplitude distributions characteristic of excitonic dimers with multiple bright states are reported and analysed. read here: https://go.shr.lc/3Y46C3D

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

I'm excited to share my first paper as a first author with the Sheldon group! Our research explores "dark and bright" character of polaritons—hybrid quasi-particles with characteristics of both light and matter utilizing our quasi-bound in the continuum (#BIC) type #metasurface array. The paper is available on #Nanophotonics: https://lnkd.in/g67uarQ8. A few highlights of our study 💡: We focused on #vibropolaritons, which emerge from the fast energy transfer between N molecular vibrations and 1 optical modes in light cavities. They have the potential to modify the energy landscape, decay dynamics, and energy transport in ground state reactions. We designed a #plasmonic #infrared cavity that supports sub-diffraction, subradiant quadrupolar resonances, which prevents coupling to free space. Interestingly, "subradiant" or "dark" polariton states are generated when quadrupolar plasmons are in resonant with carbonyl stretching modes of PMMA even though they cannot be probed by conventional #FTIR. However, they become "radiant" or "bright" as a function of the incident angle due to their quasi-bound in the continuum (BIC) type dispersion. The results also suggested that N-1 molecular states as a result of collective coupling are "radiant" or "bright" states, opening possibilities for easier analysis using conventional far-field spectroscopies.