ABSTRACT
This chapter reviews recent experimental investigations on the excitation and control of spin waves propagating in microscopic magnonic waveguides by using spin-transfer torque (STT) phenomena. It discusses the excitation of propagating guided spin waves by utilizing traditional STT devices driven by spin-polarized electric current. The chapter shows that pure spin currents created by the nonlocal spin-injection (NLSI) mechanism can be utilized for the efficient excitation of propagating spin waves with large propagation length and short spin-wave packets with the duration down to a few nanoseconds. Although the emission of spin waves due to the spin-transfer torque was theoretically predicted already in the first works on the subject, its direct experimental observation became possible only recently with the development of micro-focus Brillouin light scattering (BLS) spectroscopy. The obtained results provided a proof-of-principle demonstration of the possibility to utilize spin-torque nano- oscillators (STNOs) as nanoscale emitters for magnonic applications.
