Publications related to Controlling the helicity of magnetic skyrmions in a beta-Mn-type high-temperature chiral magnet

Global fluid simulation of plasma turbulence in stellarators with the GBS code

Joaquim Loizu Cisquella, Paolo Ricci, António João Caeiro Heitor Coelho

The implementation of three-dimensional magnetic fields, such as the ones of stellarators, in the GBS code (Ricci et al 2012 Plasma Phys. Control. Fusion54 124047; Giacomin et al 2022 J. Comput. Phys.464 111294) is presented, and simulation results are dis ...

IOP Publishing Ltd2024

Spin-Reorientation-Driven Linear Magnetoelectric Effect in Topological Antiferromagnet Cu3TeO6

Helmuth Berger

The search for new materials for energy -efficient electronic devices has gained unprecedented importance. Among the various classes of magnetic materials driving this search are antiferromagnets, magnetoelectrics, and systems with topological spin excitat ...

Amer Physical Soc2024

Gyrokinetic simulations of turbulence in magnetic fusion plasmas using a delta-f PIC scheme with evolving background

Moahan Murugappan

Using the GKEngine code which simulates an electrostatic plasma with adiabatic electron response under a sheared-slab geometry, an attempt at developing a hybrid approach between the delta-f and full-f schemes to describe plasma profiles exhibiting high fl ...

EPFL2024

Global fluid simulations of plasma turbulence in stellarators

António João Caeiro Heitor Coelho

In order to cope with the decarbonization challenge faced by many countries, fusion is one of the few alternatives to fossil fuels for the production of electricity. Two devices invented in the middle of the previous century have emerged as the most promis ...

EPFL2024

Chiral magnetohydrodynamics with zero total chirality

Kohei Kamada, Jennifer Waltraud Schober

We study the evolution of magnetic fields coupled with chiral fermion asymmetry in the framework of chiral magnetohydrodynamics with zero initial total chirality. The initial magnetic field has a turbulent spectrum peaking at a certain characteristic scale ...

American Physical Society2023

Hierarchy of quasisymmetries and degeneracies in the CoSi family of chiral crystal materials

Yi-Chiang Sun, Philip Johannes Walter Moll, Chunyu Guo

In materials, certain approximated symmetry operations can exist in a lower-order approximation of the effective model but are good enough to influence the physical responses of the system, and these approximated symmetries were recently dubbed "quasisymme ...

AMER PHYSICAL SOC2023

Murunskite - a new class of functional material

Davor Tolj

The subject of the present work is discovery and in-depth characterization of a new class of functional materials. Tuning of the bond polarity and orbital occupation with a goal of establishing balance between localization and delocalization of electrons - ...

EPFL2023

Equilibrium pressure limits in stellarators

Antoine Baillod

This thesis delves into the potential of magnetic fusion energy, and in particular focuses on the stellarator concept. Stellarators use external coils to produce 3-dimensional (3D) magnetic fields that confine a thermonuclear plasma in a topologically toro ...

EPFL2023

Five-Membered Rings Create Off-Zero Modes in Nanographene

Oleg Yazyev, Kristians Cernevics, Ziyi Wang

The low-energy electronic structure of nanographenes can be tuned through zero-energy pi-electron states, typically referred to as zero-modes. Customizable electronic and magnetic structures have been engineered by coupling zero-modes through exchange and ...

Amer Chemical Soc2023

The MAgnet Design Explorer algorithm (MADE) for LTS, Hybrid or HTS toroidal and poloidal systems of a tokamak with a view to DEMO

The European Roadmap to Fusion Electricity (Federici et al., 2018) [1] details the path to complete within the next three decades the DEMOnstration power plant, DEMO, aiming to a net gain of Energy Q=40. The 2018 DEMO baseline considers a 2 GW tokamak devi ...

2023

Hybridization driving distortions and multiferroicity in rare-earth nickelates

Nicola Marzari, Iurii Timrov, Michele Kotiuga, Luca Binci

For decades transition-metal oxides have generated a huge interest due to the multitude of physical phenomena they exhibit. In this class of materials, the rare-earth nickelates, RNiO3, stand out for their rich phase diagram stemming from complex couplings ...

Amer Physical Soc2023

Fermi energy determination for advanced smearing techniques

Nicola Marzari, Flaviano José Dos Santos

Smearing techniques are widely used in first-principles calculations of metallic and magnetic materials where they improve the accuracy of Brillouin-zone sampling and lessen the impact of level-crossing instabilities. Smearing introduces a fictitious elect ...

AMER PHYSICAL SOC2023

Progress in the design and manufacturing of the EDIPO 2 cryostat

Pierluigi Bruzzone, Kamil Sedlák, Roberto Guarino, Evgeny Solodko

A major upgrade of the European DIPOle (EDIPO) test facility, which will allow the testing of superconducting samples both for fusion and for high-energy physics applications, is taking place at the Swiss Plasma Center. With a target background field of 15 ...

2023

Equilibrium β-limits dependence on bootstrap current in classical stellarators

Jonathan Graves, Joaquim Loizu Cisquella, Antoine Baillod

While it is important to design stellarators with high magnetohydrodynamic stability β-limit, it is also crucial to ensure that good magnetic surfaces exist in a large range of β values. As β increases, pressure-driven currents perturb the vacuum magnetic ...

Cambridge University Press2023

Decay law of magnetic turbulence with helicity balanced by chiral fermions

Kohei Kamada, Jennifer Waltraud Schober

In plasmas composed of massless electrically charged fermions, chirality can be interchanged with magnetic helicity while preserving the total chirality through the quantum chiral anomaly. The decay of turbulent energy in plasmas such as those in the early ...

AMER PHYSICAL SOC2023

Laser powder bed fusion of Fe-based shape memory alloys for novel structural metamaterials and "smart" structures

Irene Ferretto

Laser powder bed fusion (LPBF) is a powder-based additive manufacturing (AM) technique, which shows great potential in the production of complex-shaped parts with unprecedented design freedom. In addition, it allows for an active manipulation of the micros ...

EPFL2023

3D Characterisation of Turbulent Plasma Filaments Using Gas Puff Imaging in the Tokamak à Configuration Variable

Nicola Offeddu

A key challenge for the development of fusion reactors based on magnetic confinement, such as tokamaks and stellarators, is the control of the turbulent processes. The most prominent feature of turbulence in the Scrape-Off Layer (SOL), the volume between t ...

EPFL2023

Synthesis and Characterization of Functionalized Spacer Cations for the Incorporation in Layered Perovskites

Simon Nussbaum

Layered hybrid organic-inorganic perovskite (LHOIP) materials are an emerging class of semiconductors endorsed as a more stable alternative compared to the more widely investigated 3D hybrid organic-inorganic halide perovskites (HOIP). Consisting of altern ...

EPFL2023

Spin Textures in 2D Magnets

Lukas Powalla

The continuous reduction of the structural size in nanotechnology slowed down over the last decade, approaching the natural limit of single atoms as building blocks of matter. Therefore, intensive research is directed toward exploring new frontiers, in par ...

EPFL2023

Magnetism and metal-organic self-assembly of rare-earth atoms on decoupling layers

Sébastien Reynaud

This thesis presents investigations of magnetic and structural properties of two dimensional metal-organic frameworks and of single atoms, both adsorbed on decoupling layers grown on metal surfaces, with focus on rare earth elements. We first report on a ...

EPFL2022