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 withatomic number65 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 theirmagnetic 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 storagedevices, 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, anultrashort laser pulsecould 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.