  As a non-magnetic heavy metal is attached to a ferromagnet, a vertically
flowing heat-driven spin current is converted to a transverse electric voltage,
which is known as the longitudinal spin Seebeck effect (SSE). If the
ferromagnet is a metal, this voltage is also accompanied by voltages from two
other sources, i.e. the anomalous Nernst effect in both the ferromagnet and the
proximity-induced ferromagnetic boundary layer. By properly identifying and
carefully separating those different effects, we find that in this pure spin
current circuit the additional spin current drawn by the heavy metal generates
another significant voltage by the ferromagnetic metal itself which should be
present in all relevant experiments.
