  Electric generation of spin current via spin Hall effect is of great interest
as it allows an efficient manipulation of magnetization in spintronic devices.
Theoretically, spin current can be also created by a temperature gradient,
which is known as spin Nernst effect. Here, we report spin Nernst
effect-induced transverse magnetoresistance in ferromagnet (FM)/non-magnetic
heavy metal (HM) bilayers. We observe that the magnitude of transverse
magnetoresistance (i.e., planar Nernst signal) in FM/HM bilayers is
significantly modified by HM and its thickness. This strong dependence of
transverse magnetoresistance on HM evidences the spin Nernst effect in HM; the
generation of thermally-induced spin current in HM and its subsequent
reflection at the FM/HM interface. Our analysis of transverse magnetoresistance
shows that the spin Nernst angles of W and Pt have the opposite sign to their
spin Hall angles. Moreover, our estimate implies that the magnitude of the spin
Nernst angle would be comparable to that of the spin Hall angle, suggesting an
efficient generation of spin current by the spin Nernst effect.
