In a world’s first, scientists have demonstrated a novel method to make magnets out of inherently non-magnetic metals. The discovery could lead to the development of new magnets for diverse applications like power generators or hard drives.
Fatma Al Ma’Mari, from the School of Physics & Astronomy at the University of Leeds, intones that the development opens new paths to devices that use abundant and hazardless elements, such as carbon and copper.
Future technologies, such as quantum computers, will require a new breed of magnets with additional properties to increase storage and processing capabilities. The new research is a step towards creating such ‘magnetic metamaterials’ that can eventually fulfil this need.
Despite their widespread use, at room temperature only three elements are ferromagnetic – iron, cobalt and nickel. The condition that determines whether a substance is ferromagnetic is called the Stoner Criterion. It explains why iron is ferromagnetic while manganese is not, even though the elements are found side-by-side in the periodic table.
It states that for an element to be ferromagnetic, when you multiply the number of different states that electrons are allowed to occupy in orbitals around the nucleus of an atom – called the Density of States (DOS) – by something called the ‘exchange interaction’, the result must be greater than one.
The new study, led by the University of Leeds, has shown how to change the exchange interaction and DOS in non-magnetic materials by removing some electrons using an interface coated with a thin layer of the carbon molecule C60, which is also called a ‘buckyball.’
The charge transfer at the interface between the two layers has changed the magnetic properties of the material so much that it became ferromagnetic and can thus be permanently magnetized.
The team used slow muons at the Paul Scherrer Institute (PSI) in Switzerland to study the magnetic properties of the interface. Slow muons are ideal for this type of investigation because they can be placed very precisely in the vicinity of the interface area and are very sensitive to their magnetic environment.
The researchers say that the study has successfully demonstrated the technique, but that further work is needed to make these synthetic magnets stronger.
Image courtesy of The University of Leeds