  The spin-Seebeck effect (SSE) in platinum (Pt) and tantalum (Ta) on yttrium
iron garnet (YIG) has been investigated by both externally heating the sample
(using an on-chip Pt heater on top of the device) as well as by current-induced
heating. For SSE measurements, external heating is the most common method to
obtain clear signals. Here we show that also by current-induced heating it is
possible to directly observe the SSE, separate from the also present spin-Hall
magnetoresistance (SMR) signal, by using a lock-in detection technique. Using
this measurement technique, the presence of additional 2nd order signals at low
applied magnetic fields and high heating currents is revealed. These signals
are caused by current-induced magnetic fields (Oersted fields) generated by the
used AC-current, resulting in dynamic SMR signals.
