Spin valves as magnetically switchable spintronic THz emitters

Abstract

In this Letter, we demonstrate that spin valve systems consisting of a magnetically soft free Fe layer and a magnetically hard Fe fixed layer pinned by an antiferromagnetic Ir23Mn77 layer, which are separated by a Pt or W spacer, are efficient switchable spintronic terahertz (THz) emitters. We show that a small external magnetic field on the order of 10 mT is sufficient to switch the magnetization orientation of the free layer and, therefore, to change the relative magnetization orientation of the two Fe layers. This goes along with a change in the THz RMS amplitude by up to more than one order of magnitude and allows fast switching of the emitter from a high to a low THz power state and vice versa.