The spin Peltier effect (SPE), heat-current generation due to spin-currentinjection, in various metal (Pt, W, and Au single layers and Pt/Cubilayer)/ferrimagnetic insulator (yttrium iron garnet: YIG) junction systemshas been investigated by means of a lock-in thermography (LIT) method. The SPEis excited by a spin current across the metal/YIG interface, which is generatedby applying a charge current to the metallic layer via the spin Hall effect.The LIT method enables the thermal imaging of the SPE free from theJoule-heating contribution. Importantly, we observed spin-current-inducedtemperature modulation not only in the Pt/YIG and W/YIG systems but also in theAu/YIG and Pt/Cu/YIG systems, excluding the possible contamination by anomalousEttingshausen effects due to proximity-induced ferromagnetism near themetal/YIG interface. As demonstrated in our previous study, the SPE signals areconfined only in the vicinity of the metal/YIG interface; we buttress thisconclusion by reducing a spatial blur due to thermal diffusion in an infraredemission layer on the sample surface used for the LIT measurements. We alsofound that the YIG-thickness dependence of the SPE is similar to that of thespin Seebeck effect measured in the same Pt/YIG sample, implying the reciprocalrelation between them.
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