In a groundbreaking study, physicists have managed to alter the magnetic properties of rare earth elements using laser pulses for the first time. This discovery overturns the previously held belief that these properties were immutable. The breakthrough opens up possibilities for developing faster, more efficient, and advanced data storage devices. The research involved two advanced X-ray lasers, EuXFEL (European X-ray Free-Electron Laser) and FLASH (Free-Electron Laser in Hamburg), both located in Hamburg, Germany.

Femtosecond Laser Pulses: X-ray lasers facilitate the observation of fundamental processes in elements. The EuXFEL and FLASH lasers can produce extremely brief X-ray pulses. According to the study’s authors, “These X-ray sources enable us to observe fundamental processes in magnetic materials on timescales as brief as a few femtoseconds.” A femtosecond is one-millionth of a billionth of a second. This advanced capability has unlocked new possibilities for studying and manipulating the behavior of rare-earth elements with unprecedented precision.

Femtosecond Laser Pulses: The researchers targeted the 4f electrons of terbium, a rare-earth metal with eight electrons in its 4f orbitals. By exposing terbium samples to X-ray laser pulses from FLASH and EuXFEL, they examined the metal’s electronic structure through X-ray spectroscopy. This process caused a temporary redistribution of the 4f electrons, leading to a shift in terbium’s magnetic properties. The study’s authors observed an “ultrafast change in 4f orbital states.”

Femtosecond Laser Pulses: The new capability to control the magnetic properties of rare-earth metals has the potential to transform data storage technology. It could significantly improve heat-assisted magnetic recording (HAMR) devices, such as hard disk drives, which currently use metal alloys with elements like iron, platinum, and cobalt.

The researchers pointed out that “with the more powerful rare-earth magnets, an ultrashort laser pulse could excite the 4f electrons and facilitate switching—an electronic effect that could be faster and more efficient than the heating mechanism used in HAMR memory.”