A new way to control the magnetic properties of rare earth elements

Terbium studied at the X-ray lasers EuXFEL and FLASH

The team carried out experiments at the X-ray lasers EuXFEL and FLASH and analyzed samples of terbium, a rare earth element with atomic number 65 and a total of 8 electrons in 4f orbitals. The sample was excited with an ultrashort laser pulse and analyzed by X-ray spectroscopy.

The soft X-ray radiation used in the study is able to determine the electronic structure of a material very sensitively. The experiment shows that after laser excitation, 4f electrons briefly switch to an orbital with a different spatial distribution. This is due to a scattering process with 5d electrons, which had not been considered before. The redistribution of the 4f electrons by the laser excitation causes a brief switch in their magnetic properties.

Rare earth materials as data storage devices

This controlled switching opens up new applications for rare earth materials, such as energy-efficient and fast information storage devices. Until now, rare earths have not been used in magnetic storage media.

The latest storage media are so-called HAMR (Heat-Assisted Magnetic Recording) data storage devices, in which magnetic structures are heated by a laser pulse in order to be switched by a magnet.

With the much stronger rare-earth magnets, an ultrashort laser pulse could now excite the 4f electrons and enable switching—an electronic effect that would be even faster and more efficient than the heating mechanism in HAMR memory.

https://phys.org/news/2024-07-magnetic-properties-rare-earth-elements.html