The fabrication and characterization of spintronic terahertz emitter using magnetic/non-magnetic bilayer with nanometer thickness

Recent innovations in spintronics have introduced a new approach to THz wave generation by exploiting ultrafast spin dynamics within magnetic/nonmagnetic heterostructures. This approach is promising as a compact and efficient terahertz wave source based on rapid advances in magnetic material fabrication and ultrafast laser technology. In this paper, nano-order controlled magnetic (Fe)/non-magnetic (Pt) bilayers are fabricated on glass substrates using magnetron sputtering, a cost-effective method for large area deposition. The thin films are characterized and their thickness dependence on spintronic terahertz emission performance is investigated. The magnetic films obtained in this study are characterized by XPS and identified as Fe₃O₄ rather than Fe metal; the Fe₃O₄ films function as the magnetic layers in STE devices and show good and stable performance over a wide range of film thickness (5–10 nm) compared to that of Fe metal films (1.5–2.5 nm). To analyze the performance, a one-dimensional model is constructed, and the analytical results are discussed.