Composition-dependent ultrafast THz emission of spintronic CoFe/Pt thin films

We measure the transient THz emission of ultrathin spintronic bilayers composed of a cobalt–iron alloy (CoxFe1−x) and platinum (Pt), depending on the Co content 0 ≤ x ≤ 1. We find that the THz emission amplitude changes only slightly over the entire concentration range, indicating that Fe and Co contribute similarly to the THz generation process. Additionally, we fabricate multilayer stacks and find that the THz amplitude is increased by up to 36% compared to a single bilayer CoFe/Pt spintronic emitter.