22.03.2014 11:15

Iron “patch” in graphene promises good magnetic characteristics

… However, a new method of creating a two-dimensional “spots” as part of the graphene sheet can detect unusual quality and other materials.

Mark Rümmeli , together with colleagues at the Institute of Solid State Physics and Materials Science. Leibniz (Germany) tried to “cross” iron with graphene – and got quite interesting results.

Grown by vapor phase deposition of graphene sheet scientists treated with a solution, which consisted of chlorine and iron. As a result, graphene remains very little iron. The sheet is then bombarded by an electron beam, creating a hole in it and provoked the iron atoms on the “spread” on the sheet. Due to the fact that at the edges of graphene structures always “hang out” extra connection, iron most actively “dragged” it to them, then these atoms joined to other iron atoms. In such conditions all the holes created in graphene were filled two-dimensional structure of the iron atoms – are not found as such in vivo.


Iron atoms (shown in orange), fill a tiny hole in a sheet of graphene (Vector Mark Rümmeli).

Unfortunately, most of the sheet had a total width of 10 atoms. And, as shown by thermodynamic calculations, the theoretical maximum width of such formations is only slightly more – 12 atoms, or about 3 nm. As soon as the “iron spots” exceeds these values, the tendency to form three-dimensional structures begins to take up over the two-dimensional graphene imposed on others.

Nevertheless, even such small structures represent a very interesting object for research. The fact that, according to calculations, “flat iron” should have a very large magnetic moment, far surpassing conventional iron. Why? In ordinary crystals of this material is part of the magnetic moment of mutually extinguished, while in the two-dimensional structure of atoms weaker magnetism affect the neighbors. According to the authors, these “nanopyatna” iron with a large magnetic moment can be very effective as part of magnetic data storage devices, although it is now that we need to clarify the long-term basic research.

You are probably wondering, what kind of potential practical applications can be discussed if calculations show instability sheets wider 12 atoms? Presumably, the stability of iron inclusions can be significantly improved coated sheet comprising such “spots”, two pure graphene sheets at the top and bottom that will not leave the iron atoms of these nanostructures.

But assume for magnetic media only or even the most promising method of new nanostructures, of course, premature. “History has shown that when someone gets a new extraordinary result, anyone certainly unexpected recipe reports on the use of this material” – philosophically says Mr. Ryummeli. By the way, his words well illustrates the same graph.

What’s next? Scientists hope to implement nanoinclusions in graphene sheets with other materials that will give them unusual properties due to a two-dimensional, without loss of magnetic and other indicators of the source material.