Of the 91 metals that we know to exist, only three are truly magnetic at room temperature: iron, cobalt and nickel. This poses something of a problem as we have to rely heavily on these elements for anything for which we need magnetism, like MRI scanners, computer memory storage and wind turbines.
But what if we could make more of these 91 metals magnetic? That’s exactly what a team of scientists led by the University of Leeds has been able to do, turning the non-magnetic materials manganese and copper magnetic. Although the effect was fairly weak, the research published in Nature Materials Science is hugely promising. And they think that the method they used could be applied to almost any metal.
“Being able to generate magnetism in materials that are not naturally magnetic opens new paths to devices that use abundant and hazardless elements, such as carbon and copper,” said co-lead author Fatma Al Ma’Mari of the University of Leeds in a statement.
“Future technologies, such as quantum computers, will require a new breed of magnets with additional properties to increase storage and processing capabilities. Our research is a step toward creating such ‘magnetic metamaterials’ that can fulfil this need.”
Almost all metals can be made to temporarily respond to magnetism, albeit some extremely weakly, known as paramagnetism and diamagnetism. But only iron, cobalt and nickel can become permanent magnets, known as ferromagnetism. A common example of a ferromagnet is a fridge magnet.
In the research, very thin layers of copper and manganese were coated in a layer of organic molecules known as buckyballs, spheres of 60 carbon atoms about one nanometer thick. Doing so removed some electrons from the metals and allowed them to overcome the Stoner Criterion – which essentially dictates why some metals are ferromagnetic and some are not.
Coauthor Oscar Cespedes, also from the University of Leeds, told IFLScience that the effect they were able to produce was very small. The strength of the magnetic copper was about 10 times weaker than nickel, and 30 times weaker than iron. Magnetic manganese was about half that.
In addition, the ferromagnetic effect was lost over time as oxidation took electrons from the metals, causing the magnetism effect to disappear. In this regard, manganese fared better than copper.
The effect was caused by the buckyballs mixing with the atoms of the metals, so the researchers also found that making the metal film more than a few millimeters thick prevented magnetism from occurring, meaning that it can’t be scaled up to practical applications just yet. But Cespedes said that it might be possible to dissolve buckyballs or other molecules that can take electrons, such as carbon nanotubes, in the metal by first liquefying it. This could allow a much larger amount of non-magnetic metal to be turned ferromagnetic.
And the applications are numerous. Cespedes in particular notes that computer memory storage, while it “doesn’t capture the imagination of curing cancer or medical imaging,” could benefit hugely and help reduce humanity’s carbon footprint.
“The amount of information we need to store is humongous,” he said. “In the last two years, we have stored as much information as in the rest of our history. So we need to find a way to store it in a very efficient way, by using materials that do not harm the environment.”
The researchers will now try to enhance the effect, in the hope that some of the numerous practical applications can be fulfilled.