Spintronic terahertz emission from Ni/Pt, Ni/Au, and Ni/Ti bilayer films grown on MgO via electron beam deposition
We report on the growth and terahertz (THz) spintronic emission of bilayer thin films consisting of ferromagnetic/nonmagnetic (FM/NM) metals. The FM metal used is Ni, while the the NM metals used are Pt, Au and Ti. The bilayer films were grown using electron beam deposition on MgO substrates, with nominal FM/NM layer thickness of 7 nm/6 nm. With an applied magnetic field of 20 mT, the THz spintronic emission intensities from the samples were measured using THz time-domain spectroscopy. The relative THz intensities exhibited by the different bilayer films (ETHzNi/Pt > ETHzNi/Au > ETHzNi/Ti) may be explained by the spin-Hall angles of the nonmagnetic metals affecting the spintronic THz emission efficiency.