Assistant Professor Ezio Iacocca, Ph.D., of the Department of Physics and Energy Science and his co-authors recently published an article with groundbreaking results on the speed that domain walls of certain multilayered ferromagnetic materials can move at without breakdown.
Iacocca, with first author Rahul Jangid of UC Davis, Thomas J. Silva of National Institute of Standards and Technology (NIST), Professor Roopali Kukreja of UC Davis and other experts shared their findings in an article titled “Extreme Domain Wall Speeds under Ultrafast Optical Excitation.” Not only was the piece published in Physical Review Letters (PRL), the American Physical Society’s primary publication, but it was chosen to be an Editor’s Suggestion – papers selected by PRL to be specifically highlighted – and was further featured in Physics Magazine.
“UCCS contributed by proposing the argument on curvature dependence and providing numerical simulations supporting the conjecture,” noted Iacocca. “These simulations were later used to aid the experimental data analysis, and subsequently help determine the domain-wall speeds.”
Along with confirming a theory previously met with skepticism in the physics community, the discovery has potential for improved memory in data storage for next-generation computing devices.
“There is great interest in using domain walls in nanoscale magnets for memory applications in microelectronics,” Silva explained. “Such memory is promising because it is nonvolatile, power efficient, and possibly very fast. However, there is an open question as to how fast such a memory can be. This comes back to knowing the fundamental limits on the speed of domain walls, and we have found that the maximum speed of domain walls is much faster than previously believed.”
“Publication of these results was a major triumph for our entire team,” he continued. “This new publication effectively ended any lingering skepticism by proving once and for all that this phenomenon of diffraction pattern distortions is not an artifact of the measurement, and is even in qualitative agreement with recently published theory.”
“Magnetism has been of keen interest to the scientific community due to its numerous applications in data storage technologies,” added Jangid. “According to recent reports, more than 85% of the world’s data is stored in Hard Disk Drives, which are based on magnetic field-based switching of magnetic material to store information. Every time information is modified in these drives, domain wall motion needs to occur. Our research is focuses on finding the fundamental speed limit for domain wall motion.”
The experimental aspect of the work was conducted using the EUV free electron laser at the Elettra Synchrotron in Trieste, Italy. Instruments like this free electron laser are few, but more experiments and study regarding this discovery are expected in the future. Both the experimental work and publication were the result of significant contributions from several field experts and organizations.
“This work would not have been possible without the interdisciplinary collaboration between multiple institutions that bought together the specialized expertise needed to conduct these challenging experiments,” Jangid said.
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