Low-temperature suppression of the spin Nernst angle in Pt

The coupling between electrical, thermal, and spin transport results in a plethora of novel phenomena. However, disentangling different effects is experimentally very challenging. We demonstrate that bilayers consisting the antiferromagnetic insulator hematite ($\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$) Pt allow one to precisely measure transverse Nernst magnetothermopower (TSNM) observe low-temperature suppression platinum (Pt) angle. show observed signal stems from interplay interfacial accumulation originating effect orientation N\'eel vector $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$, rather than its net magnetization. Since latter negligible an antiferromagnet, our device superior ferromagnetic structures, allowing unambiguously distinguish TSNM thermally excited magnon transport, which usually dominates ferri/ferromagnets due their nonzero Evaluating temperature dependence effect, we vanishing below $\ensuremath{\sim}100\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. compare these with theoretical calculations temperature-dependent conductivity find excellent agreement. This provides evidence for angle at low temperatures dominance extrinsic contributions effect.