First example of ferroelectrically tunable skyrmions brings new hope for next-generation magnetic memory devices
We are reaching the limits of silicon capabilities in terms of data storage density and speed of memory devices. One of the potential next-generation data storage elements is the magnetic skyrmion.
This study measured skyrmions in an ultra-thin material made of a ferromagnetic layer of strontium ruthenate (SrRuO3), overlaid with a ferroelectric layer of barium titanate (BaTiO3) and grown on a strontium titanate (SrTiO3) substrate. BaTiO3 is ferroelectric, meaning that it has a switchable and permanent electric polarization (), while SrRuO3 is ferromagnetic below 160 Kelvin (-113 Celsius). At the BaTiO3/SrRuO3 interface, the BaTiO3 ferroelectric polarization swirls the spins in SrRuO3, generating skyrmions. If the researchers flip the direction of polarization in BaTiO3, the density of the skyrmions changes.
A team at the Center for Correlated Electron Systems, within the Institute for Basic Science (IBS, South Korea), in collaboration with the University of Science and Technology of China, have reported the discovery of small and ferroelectrically tunable skyrmions. Published in Nature Materials, this work introduces new compelling advantages that bring skyrmion research a step closer to application.
It is envisioned that storing memory on skyrmions - stable magnetic perturbations of whirling spins (magnetic moments) - would be faster to read and write, consume less energy, and generate less heat than the currently used magnetic tunnel junctions.
In future memory and logic devices, 1 and 0 bits would correspond to the existence and non-existence of a magnetic skyrmion, respectively. Although numerous skyrmion systems have been discovered in laboratories, it is still very challenging to produce controllable, nanometer-sized skyrmions for our technology needs.
In this study, the researchers found out that skyrmions with a diameter smaller than 100 nanometers spontaneously form in ultrathin material, consisting of a layer of barium titanate (BaTiO3) and a layer of strontium ruthenate (SrRuO3). Below 160 Kelvin (-113 Celsius), SrRuO3 is ferromagnetic, meaning that its spins are aligned uniformly in a parallel fashion.
When the two layers are overlaid, however, a special magnetic interaction swirls SrRuO3's spins, generating magnetic skyrmions. Such peculiar magnetic structure was detected below 80 Kelvin (-193 Celsius) by using magnetic force microscopy and Hall measurements.
In addition, by manipulating the ferroelectric polarization of the BaTiO3 layer, the team was able to change the skyrmions' density and thermodynamic stability. The modulation is non-volatile (it persists when the power is turned off), reversible, and nanoscale.
"Magnetic skyrmions and ferroelectricity are two important research topics in condensed matter physics. They are usually studied separately, but we brought them together," explains Lingfei Wang, first author of the study.
"This correlation provides an ideal opportunity to integrate the high tunability of well-established ferroelectric devices with the superior advantages of skyrmions into next-generation memory and logic devices."
Dahee Carol Kim | EurekAlert!
Exotic spiraling electrons discovered by physicists
19.02.2019 | Rutgers University
Astronomers publish new sky map detecting hundreds of thousands of previously unknown galaxies
19.02.2019 | Universität Bielefeld
Up to now, OLEDs have been used exclusively as a novel lighting technology for use in luminaires and lamps. However, flexible organic technology can offer much more: as an active lighting surface, it can be combined with a wide variety of materials, not just to modify but to revolutionize the functionality and design of countless existing products. To exemplify this, the Fraunhofer FEP together with the company EMDE development of light GmbH will be presenting hybrid flexible OLEDs integrated into textile designs within the EU-funded project PI-SCALE for the first time at LOPEC (March 19-21, 2019 in Munich, Germany) as examples of some of the many possible applications.
The Fraunhofer FEP, a provider of research and development services in the field of organic electronics, has long been involved in the development of...
For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.
The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...
Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens
Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...
Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light
When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...
The so-called Abelian sandpile model has been studied by scientists for more than 30 years to better understand a physical phenomenon called self-organized...
11.02.2019 | Event News
30.01.2019 | Event News
16.01.2019 | Event News
21.02.2019 | Earth Sciences
21.02.2019 | Trade Fair News
21.02.2019 | Life Sciences