A new type of magnetism may be useful for quantum computing

Researchers at the Swiss Light Source (SLS) particle accelerator in Switzerland have discovered a new form of magnetism called alternative magnetism. This is now the third branch of the magnetic family, along with ferromagnetism and antimagnetism, with potential for use in semiconductors and quantum computing.

Antimagnets were discovered less than a century ago, and since then, scientists have known that the physics of magnetism goes beyond ferromagnetism — which is found in materials like those used to make magnets.

Some other types of magnetism have been described before, such as permeability and paramagnetism, but these are magnetic fields that can only be applied externally. In other words, they do not form spontaneously in materials.

The two main branches can arise naturally, and are determined by spontaneous electron spin arrangements. In quantum mechanics, spin refers to the directions that particles exhibit when they are immersed in a magnetic field.

When a magnetosensitive material is exposed to a certain magnetic field, the spin of its electrons changes and becomes directed in the same direction. This generates what is called macroscopic magnetism, which makes up the magnets we know.

In antimagnetism, this magnetic arrangement occurs in an alternating direction, which is why it does not have the properties of macroscopic magnetization. In other words, they cannot be used as refrigerator magnets.

New alternative magnetic materials introduce a special combination of alternating spin arrangements (as occurs with antiferromagnets), but they do not cancel each other out. This is caused by a specific crystal symmetry, where the spin polarization of electrons can change direction in different energy bands of the material.

These properties could represent a major advance in quantum computing and other technologies that use spintronics. This is a new area in which the spin states of electrons are used to transmit information.

Spintronics has a wide range of applications, such as random access memory (RAM) memories, which are able to store data that would be lost if the computer is turned off, and semiconductor production.

Both ferromagnetic and antiferromagnetic materials are useful for spintronics, but with some limitations. With alternative magnetism, it will be possible to overcome them, because they have the best properties of their “older brothers”.

Experiments that proved the existence of alternative magnetism are described in a new article he published nature.

source: nature