International team unveils topological spin textures in an ultrathin layer at room temperature

Findings could have potential use for computing and magnetic memories.

Ever get a stubborn knot in your shoelace that seems nearly impossible to untangle? Topological knots are sort of like shoelace knots, only they are made of magnetic moments. In addition, they have the potential to dramatically improve computing capabilities, information technologies and storage platforms. An international team of scientists involving the University of Edinburgh, Argonne National Laboratory (USA), and the National High Magnetic Field Laboratory (NHMFL) (USA) have taken work a step further in the quest to harness them.

The tangles of interlaced magnetic fields, called skyrmions, merons, or magnetic textures, are spawned by spinning electrons in certain compounds. One way to visualise these magnetic vortices is to consider the swirl pattern you see when you stir a glass of water.

The team led by Dr Elton Santos from the School of Physics and Astronomy, and Dr Luis Balicas (NHMFL) has shown the swirls in atomically thin layers of a synthetic crystalline compound of iron, germanium, and tellurium (Fe5-xGeTe2). 

The researchers discovered that the magnetic vortices happened at and above room temperature, rather than at the extremely cold conditions needed in many technological applications. In addition, the team were able to measure the knots which have different topological characteristics not yet observed at the same compound until now. This could have a potential use in real-world devices, such as smart phones, external hard-drives and computers.

In terms of their detection, Dr Elton Santos explained:

You need to find a way to see the magnetic vortices: to detect their presence through an electrical signal, which creates a readable response like in a magnetic bit. What is surprising in our results is the different character of the vortices, when normally just one type would appear. Basic computing operations may take place if we understand how to switch between one to another.

Because these topological spin textures are measurable, small and stable, they hold promise for use as a basic unit in electronic information storage such as in novel Qubit for quantum technologies. The study of these complex, defect-like magnetic textures and their possible applications has taken off in recent years as physicists examine their potential. This work adds to a striking novelty in terms of topological textures of different types of spin textures at the same material, and their control via electrical/magnetic means.   

Dr Santos goes on to explain:

The hybrid character of these spin quasi-particles in a versatile material might create new technologies with tunable information storage at low energy consumption.

Funding from the ESPRC and computer resources from EPCC Cirrus were used to conduct this research. The work features in the cover of this month’s Advanced Materials.