Rare Coupling of Magnetic and Electric Properties in a Single Material
New multiferroic mechanism could lead to next-generation memory and sensing devices
Researchers at the U.S. Department of Energy's Brookhaven National Laboratory have observed a new way that magnetic and electric properties - which have a long history of ignoring and counteracting each other - can coexist in a special class of metals. These materials, known as multiferroics, could serve as the basis for the next generation of faster and energy-efficient logic, memory, and sensing technology. The researchers, who worked with colleagues at the Leibniz Institute for Solid State and Materials Research in Germany, published their findings online this month.
Ferroelectrics are materials that display a permanent electric polarization - a set direction of charge - and respond to the application of an electric field by switching this direction. They are commonly used in applications like sonar, medical imaging, and sensors.
The group used extremely bright beams of x-rays at Brookhaven's National Synchrotron Light Source (NSLS) to examine the electronic structure of a particular metal oxide made of yttrium, manganese, and oxygen. They determined that the magnetic-electric coupling is caused by the outer cloud of electrons surrounding the atom. In this particular material, the manganese and oxygen electrons mix atomic orbitals in a process that creates atomic bonds and keeps the material together. The researchers' measurements show that this process is dependent upon the magnetic structure of the material, which in this case, causes the material to become ferroelectric, i.e. have an electric polarization.