Researchers find a key cause of energy loss in spintronic materials

A study led by researchers at the University of Minnesota Twin Cities has found a property of magnetic materials that may enable engineers to develop more efficient spintronic devices in the future.

One of the main obstacles to developing better spintronic devices is an effect called “damping,” which is where the magnetic energy essentially escapes from the materials, making them less efficient. Traditionally, scientists have ascribed this property to the interaction between the electron’s spin and its motion. However, the team led by the University of Minnesota has proven that there is another factor – magnetoelastic coupling, i.e. the interaction between electron spin or magnetism and sound particles.

“Our work doesn’t say that [the original theory] is wrong, it just says that this is only part of the story, ”stated Bill Peria, lead study author and Ph.D. Student at the University of Minnesota School of Physics and Astronomy. “We were able to show that we can see this behavior with these magnetic materials, but it is actually only a relatively small fraction of the total attenuation. There is this other mechanism that can be used to dampen the magnetism that is normally not taken into account. “

The researchers used a technique called ferromagnetic resonance, which measures how much magnetic energy is released or given off. To understand the phenomenon, they had to perform this technique at multiple temperatures ranging from room temperature to 5 Kelvin, just five degrees above absolute zero and around -450 degrees Fahrenheit.

The results of the study provide a more holistic picture of the causes of attenuation. This will allow engineers to develop “ultra-low” attenuation magnetic materials that are more energy efficient and ultimately lead to higher quality computers of the future.

“Low attenuation is important to us because we are working with our staff to create devices in which magnetic excitation can propagate over great distances,” said Paul Crowell, lead author of the study and professor at the university’s School of Physics and Astronomy . “We’re trying to build the ‘wires’ in which magnetic signals can travel across a chip without losing their strength.”

In addition to Peria and Crowell, the research team included researchers Ichiro Takeuchi (professor), Xinjun Wang (postdoctoral fellow), and Heshan Yu (doctoral student) from the University of Maryland; and Seunghun Lee, Professor of Physics at Pukyong National University in Busan, South Korea.

The research was supported by the University of Minnesota’s Spintronic Materials for Advanced Information Technologies (SMART) Center, funded by nCORE, a program of Semiconductor Research Corporation sponsored by the National Institute of Standards and Technology.