Tula R. Paudel, Ph.D., assistant professor of
physics at South Dakota Mines is among the researchers who helped discover new active
materials for computer memory. The discovery could lead to increased memory
storage in a smaller space at increased computer speeds.
Paudel and the team are working with multiferroic materials
that can be electrically and magnetically polarized. Magnets inside a compass
are one example of material that can be magnetically polarized; one side of the
magnet will always point toward the magnetic north pole. In the 1920s,
researchers found that certain materials can change their polarization when an
electric current is applied. These materials are called ferroelectric. Both
electrical and magnetic polarization co-exists in multiferroic materials.
Ferroelectric materials like magnets contain
polarized regions called domains separated by thin walls. An electric field can
switch the polarization of these regions and, like a switch, record a direction
as one or a zero.
In recent years researchers have begun to study ferroelectricity
on smaller and smaller scales. This has led to a focus on the thin boundaries,
or domain walls, that separate domains. Paudel and his team found that when
they applied electric current to a very thin layer of a ferroelectric Bismuth
ferrite, they could move these walls.
The team showed that unlike a RAM on a magnetic
disk, which needs continued zaps ...