Published on May 14th, 2013 | by Tina Casey4
Graphene Gets A New Superpower: Magnetism
May 14th, 2013 by Tina Casey
Graphene is a carbon material only one atom thick, but its superhero scale strength and other unique behaviors are beginning to make it look like its own mini-Justice League (or Avengers, for you Marvel fans). In the latest development, a research team in Spain has coaxed yet another property out of graphene in the form of magnetic power. The magnetic graphene breakthrough could lead to super fast, super efficient electronic devices based on spintronics, in which the magnetic properties of a material as well as its electrical charge are manipulated.
How To Make Magnetic Graphene
The carbon atoms in graphene are arranged in a distinctive lattice pattern that looks like chicken wire. The first pioneers of graphene research obtained samples literally by lifting a layer of carbon atoms from a chunk of graphite with sticky tape, but natural graphene obtained in this way can be finicky and inconsistent. Since then researchers have developed a variety of ways to fabricate graphene film to achieve a state closer to perfection.
The magnetic graphene development comes from researchers at IMDEA-Nanosciencia Institute, and Autonoma and Complutense Universities of Madrid. The team created their graphene film by “growing” it on a ruthenium single crystal in a vacuum chamber (ruthenium is a transition metal belonging to the platinum group).
The magnetic effect appeared when the team evaporated molecules of tetracyano-p-quinodimethane (TCNQ) onto the graphene. TCNQ belongs to the cyanocarbon group of organic compounds. Under certain conditions, it acts as a semiconductor.
To confirm the effect, the team used a scanning tunneling microscope, which produces atomic-level images. It revealed that the organic molecules in TCNQ had self-organized into a regular distribution over the surface characteristic of magnetic order. Modeling studies conducted by another member of the team confirmed that the graphene enabled this behavior.
What’s The Big Deal About Magnetic Graphene?
If and when graphene can be produced for the mass market, you’ll see it replace silicon as the semiconductor of choice, leading to a whole new generation of faster, smaller, cheaper, lighter, and more energy efficient electronic devices.
Now add spintronics to the mix, and you’ve got a recipe for a quantum leap in computing power.
The difference is that conventional electronics are based only on the electrical charge of electrons in a semiconductor material, so they behave in only two states.
Electrons also have magnetic properties, aka “spin,” which adds two more states to the equation. As explained by Professor John Xiao of the University of Delaware:
“…in the presence of a magnet, an electron will take a ‘spin up’ or ‘spin down’ position, correlating to the binary states of 1 or 0 that computers use to encode and process data. One spin state aligns with the magnetic field, and one opposes it.”
The sticky wicket is getting to a place where the direction of the magnetization can be controlled, and the Delaware team has taken a step toward that with newly announced confirmation of the presence of a magnetic field generated by electrons.
Graphene In A League Of Its Own
When we say graphene is like a mini-Justice League of its own, we’re not kidding. The material was discovered barely ten years ago, in 2004, and already it has spawned thousands of research papers describing a growing array of talents.
Among some of the highlights, graphene could enable a new generation of high efficiency desalination systems based on chemical reactions rather than water pressure, which would be quite handy given the growing issue of global fresh water scarcity.
As a high-efficiency converter of light to electricity, graphene could also appear in advanced solar cells some time in the future (one research team is already working on ultra-thin flexible solar cells based on a “sandwich” structure that includes sheets of graphene).
The field of telecommunications offers another possibility, as researchers are discovering that graphene can act as a highly efficient optical amplifier.
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