Particle physics experiments

Skyrmions could be the future of computing; X-ray experiments reveal their secrets


Scientists have long known that magnetism is created by the spins of electrons that line up in certain ways. But about a decade ago, they discovered another layer of astonishing complexity in magnetic materials: Under the right conditions, these spins can form skyrmions, small vortices, or vortices that act like particles and move independently of them. atoms which generated them.

Because they are so stable and small – about 1,000 times the size of an atom – and are easily moved by applying small electrical currents, scientists are finding ways to harness them for new types of computer technology and technology. memory storage that are smaller and use less energy.

In a recent series of papers, scientists at the Berkeley Lab, SLAC National Accelerator Laboratory, and UC San Diego describe experiments that suggest that skyrmions can form a glass-like phase where their movements are so slow that they seem to be stuck, like cars. in a traffic jam. Additionally, they measured how the natural movement of skyrmions relative to each other can oscillate and change in response to an applied magnetic field, and found that this inherent movement never seems to stop completely. This pervasive fluctuation suggests that skyrmions may have a lot in common with high-temperature superconductors – quantum materials whose ability to conduct lossless electricity at relatively high temperatures may be related to fluctuating spin and charge bands of electrons.

The research team was able to observe the fluctuations of skyrmion in a thin magnetic film composed of many alternating layers of iron and gadolinium by taking snapshots with the x-ray laser beam of the coherent light source at SLAC at just 350 trillion. seconds apart. They say their method can be used to study the physics of a wide range of materials, as well as their topology – a mathematical concept that describes how the shape of an object can deform without fundamentally changing its properties. In the case of skyrmions, topology is what gives them their rugged nature, which makes them difficult to annihilate.

“I think this technique is going to develop and become very powerful in condensed matter physics because there aren’t many direct ways to measure these fluctuations over time,” said Sujoy Roy, scientist at the Advanced Light Source from Berkeley Lab. “There are a large number of studies that can be carried out on elements such as superconductors, complex oxides and magnetic interfaces. “