Physicists have long believed it was impossible to change the magnetic properties of rare-earth elements, but a new study shows for the first time that laser pulses can excite the electrons that make rare-earth materials magnetic.
These discoveries could lead to the development of better, faster and more energy-efficient data storage devices in the future.
The study authors achieved this feat using two powerful X-ray lasers, EuXFEL (European X-ray Free Electron Laser) and FLASH (Hamburg Free Electron Laser), both located in Hamburg, Germany, and capable of generating ultrashort X-ray pulses.
“These X-ray sources enable us to observe fundamental processes in magnetic materials on time scales of a few femtoseconds, where a femtosecond (10-15 seconds) is one millionth of a billionth of a second,” the study authors wrote. Said.
X-ray laser switches the orbital state of electrons
Magnetic properties of Rare Earth Elements It is determined by the activity of 4f electrons (electrons in the 4f orbitals of an atom). However, “excitations of the 4f electronic states in rare-earth (RE) metals have not previously been thought to contribute to the magnetization dynamics,” the researchers say. Note.
“So far, scientists have not yet found a way to influence the activity of these electrons. The study authors carried out an interesting experiment that targeted the 4f electrons.
The researchers took several samples of terbium (Tb), a rare-earth metal with eight electrons in its 4f orbital. X-ray laser pulse The electronic structure of the metal was studied using X-ray spectroscopy from FLASH and EuXFEL.
The laser pulse caused a redistribution of the 4f electrons, briefly resulting in a change in the magnetic properties of terbium. “We report an ultrafast change in the 4f orbital state based on inelastic electron-electron scattering between itinerant 5d electrons and localized 4f electrons,” the study authors said.
The ability to control the magnetic properties of rare earth metals opens up new avenues for their use. For example, these materials can: ham (Thermal Assisted Magnetic Recording) Storage Devices.
HAMR is an advanced data storage technology that increases the storage density of hard drives, allowing them to store information faster and more efficiently. Current generation HAMR devices use metal alloys that include platinum, iron, and cobalt.
Replacing these alloys with rare earth metals can further improve the storage density, thermal stability, and energy efficiency of HAMR hard drives.
“The much more powerful rare-earth magnets now allow ultrashort laser pulses to excite 4f electrons and enable switching, an even faster and more efficient electronic effect than the heating mechanism of HAMR memory,” the study authors note.
But this study shows a way to temporarily alter the magnetic properties of rare earth metals — it remains to be seen whether this method also produces long-term changes.
Further research will hopefully provide answers to many of these questions and reveal more attractive applications for rare-earth metals with excited 4f electrons.
of study Published in the journal Scientific advances.
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