3D magnetic interactions can lead to new forms of computing

The magnetic moment of the electrons (spin) interacts in a very peculiar way, allowing to exchange information. [Image: University of Glasgow]

Communication

A new form of magnetic interaction that takes a phenomenon hitherto seen as uniquely two-dimensional to the third dimension promises to open up a host of new possibilities for data storage and advanced computing.

Amalio Pacheco and his colleagues at the University of Glasgow in Scotland found a way to pass information from a series of tiny magnets arranged in an ultra thin film to magnets in a second film placed in parallel.

This adds an extra dimension - literally and metaphorically - to spintronics , the field of science devoted to the storage, retrieval, and processing of data using the magnetic moment, known as spin, of electrons.

Spintronics

You have certainly toyed with a pair of magnets, checking how opposing poles attract and similar ones repel. While this is true on our human scale, the way the magnets interact undergoes some significant changes as the magnets shrink - at the nanoscale, this includes the possibility of attracting and repelling each other at angles of up to 90 degrees, not just directly.

This is one of the pivots of spintronics, whose discovery won the Nobel Prize in Physics in 2007 . The benefits of these spin-off systems include low power consumption, high storage capacity and greater robustness.

Now spintronics emerges as an even more promising force, failing to be confined to a single plane. The ability to exchange information between layers adds new storage and computing potential.

"It's a bit like adding an extra note on a musical scale - it opens up a whole new world of possibilities, not just for processing and storing conventional information, but potentially for new forms of computing that we do not even think about yet," said Amalio Pacheco.

The explored phenomenon is known as chiral spin interaction. [Image: Pacheco et al - 10.1038 / s41563-019-0386-4]

3D Spintronics

The transmission of information between layers depends on what is known to physicists as chiral spin interactions, a type of magnetic force that favors a specific sense of rotation in neighboring magnets. This mechanism has already been explored, for example, to create skyrmions , another type of superpromising nanoscale magnetic object, since magnetic computation overcomes Boolean logic thousands of times .

Pacheco assembled a multilayer system consisting of ultrathin magnetic films separated by non-magnetic metal spacers. The structure of the system, and an accurate adjustment of the properties of each layer and its interfaces, creates unusual magnetic configurations, where the magnetic field of the two layers forms angles between zero and 90 degrees.

Unlike the multilayer magnets already created, the sandwich created by the team presents a predilection for clockwise configurations, a signal that there is a chiral spin interaction between the two magnetic layers.

This breaking of rotational symmetry was observed at ambient temperature and under standard environmental conditions, justifying the team's enthusiasm with the possibility of creating topologically complex 3-D magnetic configurations in spintronic technologies.

Bibliography: Symmetry-breaking interlayer Dzyaloshinskii-Moriya interactions in synthetic antiferromagnets Amalio Fernández Pacheco, Elena Vedmedenko, Fanny Ummelen, Rhodri Mansell, Dorothée Petit, Russell P. Cowburn Nature Materials DOI: 10.1038 / s41563-019-0386-4