Lasers Induce Fast Spin Reorientation in Antiferromagnets

Paula M. Powell

Unlike common ferromagnets used in everything from compasses to spintronics, antiferromagnets still have fairly limited application potential, in part because of the lack of understanding of the magnetization process for such materials. Now researchers at the University of Nijmegen in the Netherlands and Ioffe Physico-Technical Institute in St. Petersburg, Russia, have used amplified pulses from a Ti:sapphire laser to manipulate ultrafast spins of TmFeO₃.

The approach reoriented the antiferromagnetic spins in the material by several tens of degrees within only a few picoseconds. In comparison, the magnetization process reportedly takes several hundred picoseconds for a ferromagnet with a similar anisotropic energy. During the experiment, researchers used linear optical birefringence measurements to help monitor the transition between specific spin configurations in the antiferromagnet. Scientists believe this spin-reorientation technique has the potential to expand the use of antiferrogmagnets in applications such as exchange-biased devices.