A new type of magnetism “is expanding our understanding of matter”

Magnetism has been present in science since the beginning of our scientific exploration. At first we were struck by its ability to move metal objects and repel other magnets if they faced opposite poles. And now we reach a point that had been anticipated, but never confirmed: the existence of a new type of magnetism.

Magnetic materials obtain their “power” from the behavior of the atoms inside them. Within solid materials, Atoms are surrounded by electrons and they all have a property called spin., which gives each atom its own tiny magnetic field. The total spin of each atom is represented by an arrow that can point in different directions.

In ferromagnetism (one of the two types of magnetism known until now) all the spins inside the material are aligned. If another magnetic field is applied to them, the spins align and “magic” occurs. This has allowed, for example, use magnetism to create computer memories: Read/write heads detect small magnetic particles that are interpreted as ones and zeros. In the case of antiferromagnetism, this magic does not happen and the spins are placed in opposite directions.

But magnetism still held a secret. A team of scientists, led by Libor Smejkal of the Johannes Gutenberg University of Mainz, has recently found signs of a completely new class of magnetism, one with characteristics of the two types of magnetism mentioned above. It all started when Šmejkal was looking for a possible antiferromagnetic material and began working with ruthenium dioxide, a compound that showed some ferromagnetic and also antiferromagnetic characteristics. Smejkal's team called it alterimanes, since They combine the most precious characteristics of ferromagnets and antiferromagnets: They have the stability and fast spin speeds of an antiferromagnet, but spins are easier to use in computer memory.

The results have been published in Nature and predict that more than 200 materials will be altermagnetic, more than double that of ferromagnetic materials known to date. This will allow the development of new magnetic memories, faster and more efficient than current ones, more precise sensors or accelerate the arrival of the long-awaited quantum computers.

Scientists in Smejkal's laboratory have already found several materials that appear to exhibit this “fundamentally new type of magnetism,” explains Paul McClarty, who was not involved in the study, in an editorial. This finding expands our understanding of the ways matter can work”.