Ultrafast Exchange Interaction hinted at in Ferromagnetic and Antiferromagnetic Spin Reversal

A paper titled “Transient ferromagnetic-like state mediating ultrafast reversal of antiferromagnetically coupled spins”, submitted last September, has finally made it into Nature Letters, and shows some promise for increasing the reach of spin computing speed, particular to the exchange interaction between Gadolinium, Cobalt, and Iron:

…We use the element-specific technique X-ray magnetic circular dichroism to study spin reversal in GdFeCo that is optically excited on a timescale pertinent to the characteristic time of the exchange interaction between Gd and Fe spins. We unexpectedly find that the ultrafast spin reversal in this material, where spins are coupled antiferromagnetically, occurs by way of a transient ferromagnetic-like state. [ Nature ]

Such magnetic parallelization at femtoscale speeds might possibly translate to terahertz memory scales some day.