London, September 10 : Scientists at the University of Chicago have developed magnetic sensors that can work in high temperatures, and thus be used in the ceramic engines of future cars and aircraft.
The researchers have revealed that such sensors can be created by using slightly degrading samples of a well-known semiconductor material, called indium antimonide, which is valued for its purity.
Most magnetic sensors operate by detecting how a magnetic field alters the path of an electron, and they lose this capability when subjected to temperatures reaching hundreds of degrees.
Research leaders Thomas Rosenbaum and his associate Jingshi Hu, now of the Massachusetts Institute of Technology, say that exposure to high temperatures does not affect the indium antimonide magnetosensors they have 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," Nature magazine quoted Rosenbaum, the John T. Wilson Distinguished Service Professor in Physics, as saying.
The researchers say that their work typically focuses on the properties of materials observed at the atomic level when subjected to temperatures near absolute zero.
Rosenbaum had shown in a study conducted more than a decade ago that the magnetic response of two materials silver selenide and silver telluride, which did not exhibit any magnetic response at low temperatures, skyrocketed when a tiny amount of silver was added to them.
In silver selenide and silver telluride, the magnetic response disappears at room temperature, which limits their technological applications.
However now, Rosenbaum and Hu have used two methods to recreate the effect at much higher temperatures in indium antimonide.
The researchers say that disordering the material, simply grinding it up and fusing it with heat, produces the effect, and 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. Normally, in order to make large effects, you have to have pure samples," said University of Cambridge physicist Peter Littlewood.