That could be the reality of future devices that allow electrons to be manipulated by their magnetic properties as well as by their electrical charge. The ability to manipulate electrons' magnetism, in addition to controlling their charge flow, has the potential to create broad new capabilities for computers and other devices and is the basis for an emerging technology called "spintronics." A major barrier to creating such devices is finding nonvolatile magnetic semiconductor materials, ones that don't demagnetize easily. So far the only materials found that meet the requirements operate only at a decidedly uncomfortable 200 degrees below zero Celsius, about minus 328 Fahrenheit.
But now researchers at the University of Washington have demonstrated a material – a mixture of zinc oxide and cobalt first formulated in 1780 as a pigment called cobalt green – that appears capable of operating in more suitable environments and would allow electrons to be manipulated both electrically and magnetically.
"The big challenge is to develop materials that can perform these kinds of functions not just at cryogenic temperatures but at practical temperatures," said Daniel Gamelin, a UW assistant professor of chemistry. "The breakthrough with the materials we tested is that they exhibit their magnetic properties at room temperature."
Silicon-based semiconductors that incorporate many tiny transistors are at the heart of computers and an array of other devices. But while silicon chips allow complex manipulation of electrons based on their charges, current chip technology is not useful for manipulating the electrons' magnetism, or spin.
It is believed the simplest way to manipulate an electron's magnetic state in a semiconductor device is by using a semiconductor material such as silicon or zinc oxide that incorporates magnetic elements. Previous research has suggested that some such magnetic semiconductors could operate at room temperature, but there has been strong debate about whether the results actually support that conclusion.
To test cobalt green, researchers at the Pacific Northwest National Laboratory in Richland, Wash., processed zinc oxide, a semiconductor with a simple chemical structure, so a small number of zinc ions were replaced with cobalt ions, which are magnetic. Then, in Gamelin's UW lab, the cobalt ions were aligned – making the material magnetic – by exposure to zinc metal vapor, which introduces extra electrons to the zinc oxide. The magnetic properties remained strong at room temperature even when the vapor exposure ended. When the cobalt-doped zinc oxide was heated in air, the researchers observed the extra electrons dissipate and the magnetic properties disappear, in a way that demonstrated the two are interdependent.
"This work shows there is a real effect here, and there is promise for these materials," Gamelin said. "The next step is to try to get these materials to interface with silicon semiconductors."
The bright bluish-green mixture of zinc oxide and cobalt, called cobalt green or Rinman's green, was first devised as an art pigment in the 19th century by Swedish chemist Sven Rinman. The low concentration of magnetic cobalt ions made it a good candidate for testing as a spintronics material, Gamelin said.
He is corresponding author of a paper describing the work, published in the July 21 Physical Review Letters. Co-authors are Kevin Kittilstved and Dana Schwartz, UW chemistry doctoral students, and Allan Tuan, Steve Heald and Scott Chambers of the Pacific Northwest lab. The work was funded by the National Science Foundation, the Research Corp., the Dreyfus Foundation, the Sloan Foundation and the U.S. Department of Energy.
Because development of these materials is in the early stages, it is not yet clear what their final properties will be, and their final properties will determine how they can be used, Gamelin said. But eventually such materials could have profound impact on computers and digital devices, from the way they are used to their power requirements.
"For instance, the general sense is that you will use a lot less power in these devices, so you will need a lot less cooling capacity," he said. "That would be a major advance."
Vince Stricherz | EurekAlert!
APEX takes a glimpse into the heart of darkness
25.05.2018 | Max-Planck-Institut für Radioastronomie
First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied Science
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