Nijmegen research brings magnetic storage with light without heat closer

Researchers have found material in which light can change the magnetization without releasing heat. In the long run, this can enable fast magnetic storage for data centers, for example, without the disadvantage of heat build-up.

Alexey Kimel, physicist at Radboud University Nijmegen, investigated ways to use light to influence magnetization, experimenting with materials that absorb little light. He came across yttrium iron garnet, but the effect of light on this mineral was too small. “So we increased the sensitivity by adding cobalt ions to the crystal,” Kimel says.

By using small pieces of cobalt garnet, a glassy, ​​transparent material, the researcher was able to quickly reverse the polarity of magnetic spins, without releasing any heat. The direction of the spin represents the bit, and the fact that it can quickly be converted from a 0 to a 1 is due to the cobalt ions. These have a strong coupling between the spin of electrons and the magnetic field generated by the movement of electrons around the nucleus. The circular movement, and thus the magnetization, can be influenced with light.

Scientists at Radboud University already managed to influence the magnetization with light in 2007, but then they used a laser pulse. This caused such high temperatures that the magnetic order was disrupted, making the method unusable for data storage. This is possible with the new method based on cobalt grenade, although Kimel believes that his invention could eventually play a role in large data storage centers and scientific storage systems that must be able to operate under extreme conditions, such as superconductivity electronics and quantum computers. .

The Nijmegen researchers have published their work in Nature under the title ‘Ultrafast nonthermal photo-magnetic recording in transparent medium’.