Researchers at the Max Planck Institute of Microstructure Physics in Halle developed a new switching mechanism for magnetic current. The idea is to use a short electric pulse to change the magnetic transport properties of a material sandwich consisting of a ferroelectric layer between two ferromagnetic materials. The new mechanism could be used to store information in four states of a storage point, not just two - which doubles storage density or lowers the size of MRAM devices.
In ferroelectric materials, voltage switches between the two directions of an electric polarisation – depending on its polarity – not unlike when a magnetic field permanently reverses the polarity of a ferromagnet. As ions shift within the material structure during this process, the polarisation remains intact, even after the voltage has been reduced. It is possible, however, to reverse the switch again with a similarly large voltage with reversed polarity.