Scientists at the U.S. Department of Energy's Ames Laboratory have discovered the relaxation dynamics of a zero-field state in skyrmions, a spinning magnetic phenomenon that has potential applications in data storage and spintronic devices.
Skyrmions are nanoscale whirls or vortices of magnetic poles that form lattices within a magnetic material, a type of quasiparticle that can zip across the material, pushed by electrical current.
Those properties have captured the fascination of scientists, who think the phenomenon could lead to the next big advance in data storage, making digital technology even faster and smaller.
There are some big challenges to overcome, however. Until recently skyrmions were a phenomenon only observed at extreme low temperature. Also, external magnetic forces makes them currently impractical for applications.
"In order to be really useful in a device, these magnetic vortices need to be able to exist without the 'help' of an external magnetic field," said Lin Zhou, a scientist in the Ames Laboratory's Division of Materials Sciences and Engineering.
With that in mind, she and other researchers at Ames Laboratory investigated FeGe, an iron-germanium magnetic material that has demonstrated skyrmions in the highest temperature ranges to date in crystals with a similar, or B20 structure.
Ames Lab scientists with external collaborators were able to establish a skyrmion lattice in a sample through exposure to magnetic fields and supercooling with liquid nitrogen. With a high resolution microscopy method called Lorentz transmission electron microscopy (L-TEM), the team was able to observe the skyrmion lattice in zero magnetic field, and then observe the decay of the skyrmions as the temperature warmed.
This direct observation yielded critical new information about how skyrmions behave and how they revert back to a 'normal' (what scientists call metastable) magnetic state.
"We've stabilized these skyrmions without a magnetic field, and our microscopy techniques allowed us to really see how the vortices change over time, temperature, and magnetic field; we think it provides a very solid foundation for theorists to better understand this phenomenon," Zhou said.
The research is further discussed in the paper, "Relaxation Dynamics of Zero-Field Skyrmions over a Wide Temperature Range," authored by Licong Peng, Ying Zhang, Liqin Ke, Tae-Hoon Kim, Qiang Zheng, Jiaqiang Yan, X.-G. Zhang, Yang Gao, Shouguo Wang, Jianwang Cai, Boagen Shen, Robert J. McQueeney, Adam Kaminski, Matthew J. Kramer, and Lin Zhou; and published in Nano Letters.
Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems.
DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
Laura Millsaps | EurekAlert!
Capturing 3D microstructures in real time
03.04.2020 | DOE/Argonne National Laboratory
Graphene-based actuator swarm enables programmable deformation
02.04.2020 | Science China Press
Drops of water falling on or sliding over surfaces may leave behind traces of electrical charge, causing the drops to charge themselves. Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz have now begun a detailed investigation into this phenomenon that accompanies us in every-day life. They developed a method to quantify the charge generation and additionally created a theoretical model to aid understanding. According to the scientists, the observed effect could be a source of generated power and an important building block for understanding frictional electricity.
Water drops sliding over non-conducting surfaces can be found everywhere in our lives: From the dripping of a coffee machine, to a rinse in the shower, to an...
90 million-year-old forest soil provides unexpected evidence for exceptionally warm climate near the South Pole in the Cretaceous
An international team of researchers led by geoscientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have now...
The bacteria that cause tuberculosis need iron to survive. Researchers at the University of Zurich have now solved the first detailed structure of the transport protein responsible for the iron supply. When the iron transport into the bacteria is inhibited, the pathogen can no longer grow. This opens novel ways to develop targeted tuberculosis drugs.
One of the most devastating pathogens that lives inside human cells is Mycobacterium tuberculosis, the bacillus that causes tuberculosis. According to the...
An international team with the participation of Prof. Dr. Michael Kues from the Cluster of Excellence PhoenixD at Leibniz University Hannover has developed a new method for generating quantum-entangled photons in a spectral range of light that was previously inaccessible. The discovery can make the encryption of satellite-based communications much more secure in the future.
A 15-member research team from the UK, Germany and Japan has developed a new method for generating and detecting quantum-entangled photons at a wavelength of...
Together with their colleagues from the University of Würzburg, physicists from the group of Professor Alexander Szameit at the University of Rostock have devised a “funnel” for photons. Their discovery was recently published in the renowned journal Science and holds great promise for novel ultra-sensitive detectors as well as innovative applications in telecommunications and information processing.
The quantum-optical properties of light and its interaction with matter has fascinated the Rostock professor Alexander Szameit since College.
02.04.2020 | Event News
26.03.2020 | Event News
23.03.2020 | Event News
03.04.2020 | Materials Sciences
03.04.2020 | Life Sciences
03.04.2020 | Life Sciences