  The field of magnonics, which utilizes propagating spin waves for nano-scale
transmission and processing of information, has been significantly advanced by
the advent of the spin-orbit torque. The latter phenomenon can allow one to
overcome two main drawbacks of magnonic devices - low energy efficiency of
conversion of electrical signals into spin wave signals, and fast spatial decay
of spin waves in thin-film waveguiding structures. At first glance, the
excitation and amplification of spin waves by spin-orbit torques can seem to be
straightforward. Recent research indicates, however, that the lack of the
mode-selectivity in the interaction of spin currents with dynamic magnetic
modes and the onset of dynamic nonlinear phenomena represent significant
obstacles. Here, we discuss the possible route to overcoming these limitations,
based on the suppression of nonlinear spin-wave interactions in magnetic
systems with perpendicular magnetic anisotropy. We show that this approach
enables efficient excitation of coherent magnetization dynamics and propagating
spin waves in extended spatial regions, and is expected to enable practical
implementation of complete compensation of spin-wave propagation losses.
