Researchers Use World’s Fastest Light Source to Image Nanoscale Spintronics in Materials
Researchers affiliated with the Center for Extreme Ultraviolet Science and Technology (ERC EUV), an NSF-funded Engineering Research Center headquartered at Colorado State University, used bursts of laser-like X-ray beams to simultaneously capture the behavior of different microscopic bar magnets in important magnetic alloys and multilayers of iron and nickel.
The ability to observe behavior at the nanoscale level allowed the researchers to make surprising discoveries about the fastest processes in magnetic materials. These findings shed light on a rich variety of new physics at play in extremely fast magnetization dynamics of technologically important magnetic alloys and multilayer systems, uncovering which interactions are important to include in theories. This information could lead to faster and “smarter” computers because it suggests that hard drives could be engineered to enhance the delivery of optical energy to the spin system.
Strong magnets exist only because all the spins in a magnet, each of which is like a very small bar magnet with north and south poles, are lined up to point in the same direction. Although magnetism has been studied for over 2,000 years, it is still an incompletely understood phenomenon. The fundamental length and time scales for magnetic phenomena are nanometers (nm) and femtoseconds (fs, meaning 10[-15] sec). However, a comprehensive microscopic model of how spins, electrons, photons, and phonons interact does not yet exist. Moreover, many experts believe that next-generation computer disk drives will use optically assisted magnetic recording to store more data more efficiently, and with faster access. Nevertheless, many questions remain about how the delivery of optical energy can be optimized for maximum drive performance. The EUV researchers’ efforts led to new insights related to such questions.