In our day-to-day lives, it’s easy to take magnets for granted. We may not think about it, but so many important tools we use all the time use magnets to function, from computers and other consumer electronics to medical equipment. Despite this prevalence, only three natural elements have been shown to be macroscopically magnetic: iron (Fe), cobalt (Co), and nickel (Ni).
Recently, however, a new study out of the University of Minnesota, in conjunction with researchers from the University of Wisconsin and Intel, has found a fourth element to be added to this list.
The study, published in Nature Communications, demonstrates the room-temperature ferromagnetic properties of the element ruthenium—one of the platinum metals on the periodic table. The concept of ferromagnetism specifically refers to the mechanism by which materials can form permanent magnets or become attracted to magnets. Historically, its use reaches all the way back to early applications of the lodestone for navigation.
“There was a theory based on first-principles calculation—quantum mechanism—to predict that ruthenium with tetragonal structure could [become] ferromagnetic at room temperature,” corresponding author Dr. Jian-Ping Wang explained to Twin Cities Geek. From that theory, Dr. Wang, his PhD student Patrick Quarterman, and a team of other scientists set to work attempting to physically grow ruthenium in a ferromagnetic phase in their lab at the University of Minnesota. In doing this, the team “grew ultrathin ruthenium film . . . several nanometers in thickness.” Growing this thin film allowed the team to control the structure of the element’s crystal lattices, ultimately allowing them to change the physical phase of the element into one of ferromagnetism.
Ruthenium already has plenty of practical uses in society. As Dr. Wang points out, it currently has implementations in “perpendicular hard-disk media as one of seed layers” and in “spintronic read sensors as the spacer layer in synthetic antiferromagnetic structure (SAF).” Effectively, this means ruthenium is most often used in high-powered data storage and transfer techniques. With the discovery of ruthenium’s ferromagnetic properties, Dr. Wang notes that the element could further its applications in society through uses in the “semiconductor industry for spin memory and spin-logic devices for future energy-efficient computing systems.”
While the implications of this discovery are great, and there is strong interest from organizations such as C-SPIN (the Center for Spintronic Materials, Interfaces, and Novel Architectures) and companies such as Intel, Dr. Wang says there is still work to be done: “Although we demonstrated [ruthenium’s] ferromagnetism at room temperature, its magnetic anisotropy constant is still relatively low, and also we didn’t show a way to grow a highly textured tetragonal ruthenium. Those are important for real application. My group [will] continue growing this material to further fine-tune its properties for real applications in spin memory and spin logic devices. Also, we will apply the same idea and pathway to demonstrate other single element
for ferromagnetism at room temperature.”
If you would like to read the full study, check it out at the Nature Communications website.