Better Way to Store Information in Computer Memory
Spin Hall effect may enable simpler, more
reliable magnetic memory
Most computer memory (so-called random-access memory or RAM) is volatile — the computer “forgets” the information when power is removed. The technology for making non-volatile magnetic memory is undergoing rapid progress, because techniques have recently been developed to change the orientation of small magnets without magnetic fields. This allows for denser, more efficient, and less expensive memory.
Cornell researchers have demonstrated a new technique, known as the “spin Hall effect,” that allows electrical currents to “write” information (flip the direction) of tiny magnets, as sketched at right. Current flowing through a thin platinum layer leads to a deflection of electron spins that is large enough to flip the magnetization of a neighboring cobalt magnet. When no current flows, the magnet stays in place even if the device is powered off — the memory is non-volatile. To flip the spin back, the researchers simply reverse the current.
This type of memory is very simple, but it enables devices that are more reliable than competing technologies. This advance has the potential to launch a new generation of magnetic memory devices.