By substituting a few of its iron atoms with the elements scandium and magnesium, Yusuke Tokunaga and Yoshinori Tokura from the Japan Science and Technology Agency, along with Yasujiro Taguchi from the RIKEN Advanced Science Institute and their colleagues, have produced a very rare magnet. The rarity of the magnet lies in three features that, taken together, endow it with a high degree of tunability.
Firstly, the new magnet is multiferroic: its magnetization and electric polarization are linked, and each can be potentially controlled by both electrical and magnetic fields. Multiferroic materials may allow for magnetic data storage devices that do not require magnetic fields, resulting in reduced cost, power requirements, and bulk. Other applications, such as sensors, may also be possible.
Another feature of this new magnet is that its electronic spins are arranged in a helix (Fig. 1). Therefore the handedness of the helix is a controllable material quantity, along with the material’s magnetic strength and its electric polarization. By applying a magnetic field, the researchers were able to change the geometry of the helix, which in turn increased or decreased the strength of the electric polarization.
The third distinguishing feature is that the material’s spin helix structure persists even above room temperature. This contrasts with many other known multiferroic materials, which require liquid nitrogen temperatures in order to form helical spin structures. In fact, the research team studied BaFe12O19 because a related but more complex magnet demonstrated a helical spin structure at low temperature. It also proved relatively straightforward to fashion large crystals of BaFe12O19, making measurements and device manufacture easier.
The team concluded that the concentration of scandium, the temperature, and the applied magnetic field strength could all be used to control the strength and direction of the materials magnetic and electrical polarization, as well as the retention times of these polarizations. More generally, the new magnet uncovered by Tokunaga, Taguchi, Tokura and colleagues adds to the catalogue of room-temperature multiferroics, which material scientists have just begun to explore. A particularly alluring goal is the discovery of a material with magnetic and electrical ordering at room temperature and in the absence of magnetic field, says Tokunaga.
The corresponding author for this highlight is based at the Cross-Correlated Materials Research Group, RIKEN Advanced Science Institute
 Tokunaga, Y., Kaneko, Y., Okuyama, D., Ishiwata, S., Arima, T., Wakimoto, S., Kakurai, K., Taguchi, Y. & Tokura, Y. Multiferroic M-type hexaferrites with a room-temperature conical state and magnetically controllable spin helicity. Physical Review Letters 105, 257201 (2010).
 Ishiwata, S., Taguchi, Y., Murakawa, H., Onose, Y. & Tokura, Y. Low-magnetic-field control of electric polarization vector in a helimagnet. Science 319, 1643–1646 (2008).
gro-pr | Research asia research news
Electron tomography technique leads to 3-D reconstructions at the nanoscale
24.05.2018 | The Optical Society
These could revolutionize the world
24.05.2018 | Vanderbilt University
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
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...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences