The key to fabricating the sensors involves slightly diluting samples of a well-known semiconductor material, called indium antimonide, which is valued for its purity. Chicago’s Thomas Rosenbaum and associate Jingshi Hu, now of the Massachusetts Institute of Technology, have published their formula in the September issue of the journal Nature Materials.
Most magnetic sensors operate by detecting how a magnetic field alters the path of an electron. Conventional sensors lose this capability when subjected to temperatures reaching hundreds of degrees. Not so in the indium antimonide magnetosensors that Rosenbaum and Hu developed with support from the U.S. Department of Energy.
“This sensor would be able to function in those sorts of temperatures without any degradation,” said Rosenbaum, the John T. Wilson Distinguished Service Professor in Physics.
Rosenbaum’s research typically focuses on the properties of materials observed at the atomic level when subjected to temperatures near absolute zero (minus-460 degrees Fahrenheit). More than a decade ago, he led a team of scientists in experiments involving silver selenide and silver telluride, two materials that exhibited no magnetic response at low temperatures. But when the team introduced a tiny amount of silver (one part in 10,000) to the materials, their magnetic response skyrocketed.
In silver selenide and silver telluride, the magnetic response disappears at room temperature, which limits their technological applications. But Rosenbaum and Hu now have used two methods to recreate the effect at much higher temperatures in indium antimonide. Disordering the material—simply grinding it up and fusing it with heat—produces the effect. So does introducing impurities of just a few parts per million.
“What’s nice about it is that, first, it’s an unexpected phenomenon; and second, it’s a very useful one,” said University of Cambridge physicist Peter Littlewood. “Normally, in order to make large effects, you have to have pure samples.”
Before Rosenbaum and Hu’s latest experiments, two theories dueled to explain the effect. In 2003, Littlewood and Meera Parish, now a postdoctoral fellow at the Princeton Center for Theoretical Physics, explained the effect using classical physics, the laws of nature that govern physics above the atomic scale. Nobel laureate Alexei Abrikosov of Argonne National Laboratory devised an explanation based on quantum physics, the dominant physics at ultrasmall scales.
“We’ve shown that both theories work, just in different regimes,” Rosenbaum said.
Littlewood lauded the sequence of events as an example of how science ought to work. “There’s a discovery of a result. There’s a theory about it. Further experiments are done to test the theory. They work and that provokes another idea, and you bounce to and fro,” Littlewood said. “That’s how we like to describe science progressing. One is rarely lucky enough to do that over a long period.”
Steve Koppes | Newswise Science News
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