In a collaboration between experimental physicists and theoretical physicists in the framework of the Dynamics and Topology (TopDyn) excellence project, a system of many small magnetic whirls could be engineered to form a regularly ordered state. Such a transition from a disordered to an ordered phase is analogous to the well-known crystallization, which, however, occurs here in two dimensions. For the research work at Johannes Gutenberg University Mainz (JGU), experimental physicists around Professor Mathias Kläui cooperated with a group of theoretical physicists around Dr. Peter Virnau. The results have been published recently in the journal Advanced Functional Materials. The TopDyn research center is funded by the German federal state of Rhineland-Palatinate.
Two-dimensional systems are a topical area of research in theoretical and experimental physics. These systems can attain a number of exotic states and exhibit transitions that do not exist in three dimensions. One such example is the Kosterlitz-Thouless transition, for which the Nobel Prize in Physics was awarded in 2016. Another example is the so-called hexatic phase, which occurs in systems of two-dimensional hard discs in between the disordered liquid and strongly ordered solid phase.
Two-dimensional model system generated from skyrmions
In the work now presented, magnetic whirls, so called skyrmions, were realized in ultra-thin metal multilayer films. The number of skyrmions and their size could be tuned by applied magnetic fields. These are ideal conditions for the experimental realization of dense two-dimensional model systems. In particular, the researchers were able to generate an experimental system that exhibits the signature of an emerging hexatic phase. This demonstrates that the system indeed behaves like a two-dimensional system and can be described by hard discs. Furthermore, the results allowed for the determination of the repulsive interaction between skyrmions, which could be modelled by computer simulations.
"I am very glad that the joint work between the Soft Matter Theory group of Dr. Peter Virnau and our experimental group led to this exciting work. Such new collaborations are exactly the aim of the TopDyn research center," said Professor Mathias Kläui, TopDyn spokesman.
Since the properties of skyrmions can be tuned by external magnetic fields, this is an important first step towards the tailored preparation and analysis of the dynamics of two-dimensional phases and phase transitions. Perspectives of further possibilities of effects to be studied in such systems can be found in a recently published News & Views Article in Nature Nanotechnology.
The Dynamics and Topology research center was founded in 2019 as a collaborative center of Johannes Gutenberg University Mainz, TU Kaiserslautern, and the Max Planck Institute for Polymer Research in Mainz. It is funded by the state of Rhineland-Palatinate and pursues a highly interdisciplinary approach.
Reference:
Skyrmion Lattice Phases in Thin Film Multilayer
Jakub Zázvorka Florian Dittrich Yuqing Ge Nico Kerber Klaus Raab Thomas Winkler Kai Litzius Martin Veis Peter Virnau Mathias Kläui
https://doi.org/10.1002/adfm.202004037
Contact:
PD Dr. Peter Virnau
Institute of Physics, JGU Mainz
virnau@uni-mainz.de
49-613-139-20493
RASIRC announced a major expansion of its Nitride Hub program to California. The company will open a second dedicated laboratory for advanced metal nitride development at the Qualcomm Institute at UC San Diego.
certain wavelength and direction will also emit heat in the same ways. This fundamental relationship, known as reciprocity, limits our ability to independently control heat absorption and heat emission. But if absorption and emission could be separated, engineers could design devices that absorb heat from one direction while emitting it in another. By ‘steering’ thermal energy, they could create more efficient thermal management, energy conversion, infrared sensing, and thermal communicati...
MIT researchers have found that rhombohedral graphene — a naturally occurring staircase-like stack of four or five atomically thin carbon layers found in ordinary graphite — can host multiple distinct superconducting states simultaneously, a rarity among known superconductors. Publishing in Nature, the team reports that three of these states not only survive exposure to magnetic fields up to around 9 tesla (roughly 180,000 times Earth's magnetic field), which would normally destroy supercondu...
This week in nanotech
$751.8M raised
6 funding rounds · 37 deals tracked
New products
DLS-1 Mass Spectrometer for Fusion Gas AnalysisHiden Analytical Featured
Nion-compatible In Situ STEM Holders for Electrical BiasingHummingbird Scientific Featured
Fe85Cr4Mo8V2C1 wire filler materialLeibniz Institute for Solid State and Materials Research Dresden - IFW DresdenMarket insights
Last 30 days: Quantum Technologies drew the most money: $3.18B.
Money raised per month
Behind the deal
Who led Xanadu Quantum Technologies Limited’s $10M Grant?
See the investors with Insights Pro →
