Ultra-Efficient Opto-Magnetic Control of Magnetization in Nanofilms

Reviewed by Lexie Corner   on February 6, 2025

Researchers at Tohoku University have made a significant advance in magneto-optical technology. They have demonstrated magneto-optical torque that is approximately five times more efficient than conventional magnets. Study  was published in  Physical Review Letters  .  

The study, led by Professor Shigemi Mizukami, Assistant Professor Satoshi Aihama, and Mr. Koki Nokoi, has important implications for the development of spin storage and light-based memory technologies.

Magneto-optical torque is a method used to create a force on magnets that allows for more efficient reorientation using light. The research team developed alloy nanofilms containing 70 percent platinum dissolved in cobalt, showing that the relativistic quantum mechanical effects of platinum significantly enhance the magnetic moment. The study attributes this enhancement to relativistic quantum mechanical interactions and the orbital angular momentum of the electron caused by circularly polarized light.

This advance makes it possible to achieve the same magneto-optical effect with only one-fifth the previously required light intensity, helping to develop more energy-efficient magneto-optical devices. These findings not only support the design of high-performance spin memories and storage systems that use light to write data, but also provide new insight into the role of electron orbital angular momentum in metallic magnetic materials.

These advances could lead to faster and more energy-efficient devices in the future  . 

Shigemi Mizukami, professor at Tohoku University

This study is in line with the growing interest in optoelectronic fusion technologies that integrate optical and electronic methods for future applications. This is an important step in using light and magnetism to control magnetic nanomaterials.