Read slowly. This is important. It will likely allow a huge reduction in the
heat output of semi conductors in general once we learn how to master the
method and give us a wide range of new strategies.
We are certainly getting down to
manipulating individual atoms in order to make our computers. The coming wave will be surpassing our
wildest imaginings as this and graphene are worked up into our technology.
The Holodeck is quickly becoming
feasible.
On And Off Chameleon Magnets Could Revolutionize Computing
by Staff Writers
http://www.spacemart.com/reports/On_And_Off_Chameleon_Magnets_Could_Revolutionize_Computing_999.html
What causes a magnet to be a magnet, and how can we control a magnet's
behavior? These are the questions that University at Buffalo
He is one of many scientists who believe that magnets could
revolutionize computing, forming the basis of high-capacity and low-energy
memory, data storage and data transfer devices.
Today, in a commentary in Science, Zutic and fellow UB physicist John
Cerne, who studies magnetism experimentally, discuss an exciting advancement: A
study by Japanese scientists showing that it is possible to turn a material's
magnetism on and off at room temperature.
A material's magnetism is determined by a property all electrons
possess: something called "spin." Electrons can have an
"up" or "down" spin, and a material is magnetic when most
of its electrons possess the same spin. Individual spins are akin to tiny bar
magnets, which have north and south poles.
In the Japanese study, which also appears in the current issue of
Science, a team led by researchers at Tohoku University added cobalt to
titanium dioxide, a nonmagnetic semiconductor, to create a new material
that, like a chameleon, can transform from a paramagnet (a nonmagnetic
material) to a ferromagnet (a magnetic material) at room temperature.
To achieve change, the researchers applied an electric voltage to the
material, exposing the material to extra electrons. As Zutic and Cerne explain
in their commentary, these additional electrons - called "carriers" -
are mobile and convey information between fixed cobalt ions that causes the
spins of the cobalt electrons to align in one direction.
In an interview, Zutic calls the ability to switch a magnet
"on" or "off" revolutionary. He explains the promise of
magnet- or spin-based computing technology - called "spintronics" -
by contrasting it with conventional electronics.
Modern, electronic gadgets record and read data as a blueprint of ones
and zeros that are represented, in circuits, by the presence or absence of
electrons. Processing information requires moving electrons, which consumes
energy and produces heat.
Spintronic gadgets, in contrast, store and
process data by exploiting electrons' "up" and "down"
spins, which can stand for the ones and zeros devices read. Future
energy-saving improvements in data processing could include devices that
process information by "flipping" spin instead of shuttling electrons
around.
In their Science commentary, Zutic and Cerne write that chameleon
magnets could "help us make more versatile transistors and bring us closer
to the seamless integration of memory and logic by providing smart hardware
that can be dynamically reprogrammed for optimal performance of a specific
task."
"Large applied magnetic fields can enforce the spin alignment in
semiconductor transistors," they write. "With chameleon magnets, such
alignment would be tunable and would require no magnetic field and could
revolutionize the role ferromagnets play in technology."
In an interview, Zutic says that applying an electric voltage to a
semiconductor injected with cobalt or other magnetic impurities may be just one
way of creating a chameleon magnet.
Applying heat or light to such a material could have a similar effect,
freeing electrons that can then convey information about spin alignment between
ions, he says.
The so-far elusive heat-based chameleon magnets were first proposed by
Zutic in 2002. With his colleagues, Andre Petukhov of the South Dakota School
The concept of nonmagnetic materials becoming magnetic as they heat up
is counterintuitive, Zutic says. Scientists had long assumed that orderly,
magnetic materials would lose their neat, spin alignments when heated - just as
orderly, crystalline ice melts into disorderly water as temperatures rise.
The carrier electrons, however, are the key. Because heating a material
introduces additional carriers that can cause nearby electrons to adopt aligned
spins, heating chameleon materials - up to a certain temperature - should
actually cause them to become magnetic, Zutic explains.
His research on magnetism is funded by the Department of Energy, Office
of Naval Research, Air Force Office of Scientific Research and the National
Science Foundation.
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