  The rectifying effect of radio-frequency (RF) current is highly sensitive in
terms of the spatial spin distribution and dynamics. It emerged that an
additional spin wave mode was stimulated by the direct-current (DC) current and
that this spin wave was detectable via rectification of the RF current. A
phenomenological model to describe the time-dependent anisotropic
magnetoresistance or time-dependent planer Hall effect is proposed and found to
correlate well to the experimental results. The nonlinear spin dynamics
accompanying additional spin waves are studied as functions of the RF and DC
currents, the external magnetic field, and the applied field direction.
