Creating more energy efficient memory for the devices of the future

Dr. Mingzhong Wu sits at his desk in the Physics building.

Dr. Mingzhong Wu, professor of Physics, studies how topological insulators can be used to create more efficient memory devices.

A simple childhood toy, the spinning top, mimics an important movement in physics – the spinning of electrons. Just as a spinning top can rotate in either direction, so can an electron, and this subatomic movement creates spin electric current.

Mingzhong Wu, professor of physics and the director of Colorado State University’s Programs of Research and Scholarly Excellence designated Center for Advanced Magnetics, studies this electron movement as it interacts through conducting and insulating materials to affect magnetic memory and recording. His research group recently discovered a major advancement that could mean more efficient magnetic storage in memory devices.

In the article “Magnetization switching using topological surface states,” published in Science Advances in August 2019, Wu described how coupling a material called a topological insulator with a magnetic insulator allowed his team to take full advantage of the unique properties of topological insulators.

Topological insulators combine an exterior surface that is a conductor with an interior that is an insulator. Electron movement on the conducting surface creates spin currents.

Wu’s research is the first that uses a topological insulator to switch magnetization in magnetic insulators. This research, funded by the Department of Energy and the National Science Foundation, could lead to more energy-efficient magnetic memory in a variety of devices.

Collaboration is key

Wu collaborated with several scientists on this research, including Nitin Samarth, head of the Physics Department at Penn State University, and Stuart Field, a physics professor at CSU. Wu’s research group also included Peng Li, the first author of the paper; Li was a former postdoc at CSU and is now a professor at Auburn University.

“One group does not have all of the expertise needed, that is why the collaboration is important,” Wu said.

This collaboration also helped with the need to use many different sophisticated tools. Wu’s group was able to grow the magnetic insulator in CSU’s physics lab but worked with Samarth to grow the topological insulator.

“Fundamental physics is very interesting, and it also has a direct connection to real device applications,” said Wu. Industry partners have also noticed the potential for these advancements and are now supporting the magnetics program at CSU.