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
Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters
Light-driven atomic rotations excite magnetic waves
24.10.2016 | Max-Planck-Institut für Struktur und Dynamik der Materie
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Power and Electrical Engineering
25.10.2016 | Process Engineering