Magnets could be made stronger by adding non-magnetic elements
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Researchers at the US Department of Energy’s Ames Laboratory have discovered that permanent magnets can be functionalised by adding scandium to a gadolinium-germanium alloy.
Scandium is a virtually non-magnetic material, yet when it is added in small amounts to a ferromagnetic material – a material which remains magnetic in the absence of an external magnetic field – it appears to make the ferromagnet stronger.
The researchers describe this has a “counterintuitive experimental finding” in their Chemistry of Materials paper reporting their findings.
“People don’t talk much about scandium when they are talking magnetism, because there has not been much reason to,” said Dr Yaroslav Mudryk of Ames Laboratory. “It’s rare, expensive and displays virtually no magnetism.”
“Conventional wisdom says if you take compound A and compound B and combine them together, most commonly you get some combination of the properties of each. In the case of the addition of scandium to gadolinium, however, we observed an abrupt anomaly.”
The 1997 discovery of the giant magnetocaloric effect in rare earth alloys – which manifests in the heating or cooling of magnetic materials in an external magnetic field – allowed for the search for hidden properties of magnetic rare-earth compounds to begin in earnest.
These properties can be discovered by adding tiny amounts into other materials, altering their structures.
By building computational models, the researchers were able to identify an unexpectedly large magnetic moment developing when scandium was combined into gadolinium.
“Basic research takes time to bear fruit,” said Professor Vitalij Pecharsky, Ames Laboratory group leader. “Only now we have learned enough about these unique rare earth element-containing materials to become not only comfortable but precise in predicting how to manipulate their properties at will.”
According to the researchers, the discovery could change the way scandium and other conventionally non-magnetic elements are approached by magnetic materials research and development. It is possible, for instance, that grasping the properties of these unlikely elements could allow for the design of new tools for manipulating rare-earth compounds.