THz spintronic emitters: a review on achievements and future challenges

The field of THz spintronics is a novel direction in the research field of nanomagnetism and spintronics that combines magnetism with optical physics and ultrafast photonics. The experimental scheme of the field involves the use of femtosecond laser pulses to trigger ultrafast spin and charge dynamics in thin films composed of ferromagnetic and nonmagnetic thin layers, where the nonmagnetic layer features a strong spin-orbit coupling. The technological and scientific key challenges of THz spintronic emitters are to increase their intensity and to shape the frequency bandwidth. To achieve the control of the source of the radiation, namely the transport of the ultrafast spin current is required. In this review, we address the generation, detection, efficiency and the future perspectives of THz emitters. We present the state-of-the-art of efficient emission in terms of materials, geometrical stack, interface quality and patterning. The impressive so far results hold the promise for new generation of THz physics based on spintronic emitters.