Unlike conventional magnets, antiferromagnets (such as the metal chromium) are materials which exhibit ‘secret’ magnetism, undetectable at a macroscopic level. Instead, their magnetism is confined to very small regions where atoms behave as tiny magnets. They spontaneously align themselves opposite to adjacent atoms, leaving the material magnetically neutral overall.
Professor Gabriel Aeppli, Director of the London Centre for Nanotechnology, said: “People have been familiar with ferromagnets for hundreds of years and they have countless everyday uses; everything from driving electrical motors to storing information on hard disk drives. We haven’t been able to make the same strides with antiferromagnets because we weren’t able to look inside them and see how they were ordered.
“This breakthrough takes our understanding of the internal dynamics of antiferromagnets to where we were ninety years ago with ferromagnets. Once you can see something, it makes it that much easier to start engineering it.”
The magnetic characteristics of ferromagnets have been studied by scientists since Greek antiquity, enabling them to build up a detailed picture of the regions - or “magnetic domains” - into which they are divided. However, antiferromagnets remained a mystery because their internal structure was too fine to be measured.
The internal order of antiferromagnets is on the same scale as the wavelength of x-rays (below 10 nanometers). The latest research used x-ray photon correlation spectroscopy to produce ‘speckle’ patterns; holograms which provide a unique ‘fingerprint’ of a particular magnetic domain configuration.
Dr. Eric D. Isaacs, Director of the Center for Nanoscale Materials, said: “Since the discovery of x-rays over 100 years ago, it has been the dream of scientists and engineers to use them to make holographic images of moving objects, such as magnetic domains, at the nanoscale.
“This has only become possible in the last few years with the availability of sources of coherent x-rays, such as the Advanced Photon Source, and the future looks even brighter with the development of fully coherent x-ray sources called Free Electron Lasers over the next few years.”
In addition to producing the first antiferromagnet holograms, the research also showed that their magnetic domains shift over time, even at the lowest of temperatures. The most likely explanation for this can be found in quantum mechanics and the experiments open the door to the future exploitation of antiferromagnets in emerging technologies such as quantum computing.
“The key finding of our research provides information on the stability of domain walls in antiferromagnets,” said Oleg Shpyrko, lead author on the publication and researcher at the Center for Nanoscale Materials. “Understanding this is the first step towards engineering antiferromagnets into useful nanoscale devices that exploit it.”
Work at the London Centre for Nanotechnology was funded by a Royal Society Wolfson Research Merit Award and the Basic Technologies program of Research Councils UK. Work at the Center for Nanoscale Materials and the Advanced Photon Source was supported by the DOE Office of Science, Office of Basic Energy Sciences. The work at the University of Chicago was supported by the National Science Foundation.
David Weston | alfa
Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center
A quantum entanglement between two physically separated ultra-cold atomic clouds
17.05.2018 | University of the Basque Country
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology