The special properties of rare earth magnetic materials are due to the electrons in the 4f shell. Until now, the magnetic properties of 4f electrons were considered almost impossible to control.
Now, a team from HZB, Freie Universität Berlin and other institutions has shown for the first time that laser pulses can influence 4f electrons- and thus change their magnetic properties. The discovery, which was made through experiments at EuXFEL and FLASH, opens up a new way to data storage with rare earth elements.
The strongest magnets we know of are based on rare earths. Their 4f electrons are responsible for their magnetic properties: They generate a large magnetic moment that is maintained even when their chemical environment changes. This means that rare earths can be used in very different compounds and alloys without changing their special magnetic properties.
Until now, it was assumed that the magnetic properties of 4f electrons could not be changed even if the material was excited with a laser pulse. But indeed, this is possible, as a team from HZB, Freie Universität Berlin, DESY, the European X-ray laser XFEL and other institutions has now shown.
The spatial arrangement of the 4f electrons can be briefly switched by laser excitation. This also changes their magnetism. This effect opens up new possibilities for the fast and energy-efficient control of magnetic rare-earth materials. The work has now been published in the journal Science Advances.
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