Now, an international research collaboration has brought us a large step closer to the reality of spintronics. They accomplished for the first time to measure ultrafast spin-polarized current pulses in magnetic layers. Her team, under the guidance of Professor Christine Boeglin from the University of Strasbourg, achieved unique experiments. They carried out their work at the femtoslicing station at BESSY II. Deeksha Gupta, one of the report’s principal researchers, has already defended a brilliant Ph.D. She has recently joined the Helmholtz-Zentrum Berlin (HZB) to pursue her research as a postdoctoral researcher.
The experiments focused on elucidating dynamic processes within a magnetic layer system, specifically targeting the behavior of spin currents in complex materials. This study enhances our comprehension of ultrafast spin phenomena. It sets the stage for future innovative technological developments in the field.
Research Overview
Deeksha Gupta and her colleagues employed a femtosecond infrared laser to generate hot electrons in a platinum layer over a ferrimagnetic structure composed of iron gadolinium (Fe74Gd26). These hot electrons accelerated the transport of a pure spin current. This transport took place across a cobalt/platinum multilayer spin valve structure.
By carefully tracking the demagnetization dynamics in this layered ferrimagnet, the team was able to flesh out the characteristics of the SPHE pulses. Their results provide fresh perspective, sage advice on probing ultrafast spin-polarized current pulses. This research deepens our comprehension of femtoslicing technology at BESSY II.
“This is a rapidly developing field. For the first time, we have been able to really shed light on the behavior of spin currents in complex magnetic materials. This could pave the way for faster technological developments.” – Deeksha Gupta
The Role of Theoretical Models
The team was intentional in addressing the experimental findings with robust implementation support. They came to rely upon theoretical models created by O. Eriksson and his team at Uppsala University. Notably, these models were integral to doing a parameter sweep on SPHE current pulses. Among other things, they looked closely at the effects of pulse duration and direction of spin polarization.
The combination of experimental data and theoretical insights allowed the researchers to paint a comprehensive picture of ultrafast spin dynamics. What they did, though, was to interrogate those processes with a laser focus. This enabled them to observe ultrafast demagnetization in a multilayer magnetic film in less than a few hundred femtoseconds.
Unique Capabilities of Femtoslicing Technology
Another key element of this study was the presence of the femtoslicing beamline at BESSY II. This leading-edge technology has given us unparalleled capabilities to explore ultrafast spin dynamics on different elements within intricate sample systems.
Christian Schüßler-Langeheine, another member of the research team, highlighted the importance of this technology:
“Thanks to the unique capabilities of the femtoslicing beamline at BESSY II, we can separately probe the ultrafast spin dynamics for each component of a complex sample system.”
Dissecting these dynamics with such unprecedented temporal resolution is a novel endeavor. It provides a powerful new way to explore materials physics and eventually their application to new spintronic device spaces.
Implications for Future Technologies
The research team’s findings, published in Nature Communications with the DOI 10.1038/s41467-025-58411-3, represent a landmark moment in understanding ultrafast phenomena in magnetic materials. This effort defines the characteristics of SPHE pulses and further explores their effects at rapid time scales. In turn, it opens up remarkable possibilities for innovations in storage and processing technologies that are based on spintronics.
With many more researchers entering this quickly developing space, Gupta and her colleagues offer a helpful guide. Their efforts have the potential to speed breakthroughs in technology and revolutionize industries that rely on magnetic materials and spin-based applications.