Could Magnonics Spark the Extinction of Electronics?


Electronics work by shuffling electrons through
circuits and logic gates to perform calculations, but in doing so they have to overcome resistance,
which wastes energy and generates heat. So instead of forcing electrons to push each
other along, what if we just made them do the wave? Electrons have a negative charge; it’s a
fundamental part of what they are. They also have a property called spin, and
this spin can be oriented either up or down. If the spins of the outermost electrons in
an atom are aligned the same direction, they’ll generate a magnetic field,
making the atom a tiny magnet. If all the atoms in a material have their
magnetic fields aligned the same way, the material will act as a magnet. (I could make the Insane Clown Posse joke, but I won’t. I’m not going to do it. It’s 2018 and we’re officially laying
the magnets joke to rest.) Anyway, it’s possible to reverse the direction
of the magnetic field of an atom in a material by applying energy. When that happens, the strength of the magnetic
field in that area drops a bit; it’s effectively the same as a partial reversal
of all the tiny magnets in that group. This partial reversal spreads, like a crowd
doing the wave at a stadium, passing the energy that dampened the magnetic field along. This wave of energy can also be thought of
as a particle, called a magnon. Just like electrons in a circuit, a magnon
can be used to carry information, with some advantages over moving electrons, like using
less energy and generating less heat (which is good, because sometimes I worry about what
my laptop is doing to me when it’s atop my lap.) But while the silicon circuits that conduct
electrons are relatively easy to make, the magnets that transport magnons are not. One reason we’re still using electronics
instead of magnonics is because the media that carry magnons well are notoriously hard
to make and harder to combine with other materials. Currently most magnonic researchers use a
material called yttrium iron garnet — or YIG — to carry the waves. A film of high quality YIG has to be grown
on a matching lattice structure like gadolinium gallium garnet. Hard to say, harder to combine
with other substrates, like silicon. So researchers started exploring elsewhere,
and came across a material first made in 1991. This material, called vanadium tetracyanoethylene,
was the first carbon based magnet that was stable at room temperature. Well so long as it wasn’t exposed to oxygen,
in which case it can burst into flame. But aside from the surprise fire, it’s great
for studying magnonics, keeping the magnons just as stable as YIG while they persisted
for record-breaking times. If researchers can make a practical material
for magnons to travel through, then the next step is making digital logic gates like the
transistors in a chip. Fortunately researchers don’t have to figure
out entirely new transistors that can respond to magnons. It’s possible to convert a magnon into an
electrical signal thanks to something called the inverse spin Hall effect, and then it’s
just a matter of sending electrons through the transistor like we’ve always done. This means researchers could combine magnonics
and electronics, bringing them one step closer to smaller, faster, more efficient computers. For now though researchers are exploring other
materials that might work even better than vanadium tetracyanoethylene. Hopefully they find one that doesn’t catch
fire when you crack a window. Dive deeper into the future of computing and
watch this video here, where I explain how using photons in computers instead of electrons
could make light-speed computing possible. Don’t forget to subscribe for more science
and tech videos every week, and thanks for watching!