Platinum thickness dependence and annealing effect of the spin-Seebeck voltage in platinum/yttrium iron garnet structures

Abstract

We investigate the substrate annealing effect of thermoelectric voltage induced by the spin-Seebeck effect in Pt/polycrystalline yttrium iron garnet Y3Fe5O12 (YIG) structures with different Pt thicknesses. The thermoelectric voltage is increased by decreasing the Pt thickness to 1.9 nm as well as by annealing. Annealing at 1073 K for 5 h enhances the thermoelectric voltage up to 7.4 µV/K in structures with 1.9 nm Pt thickness.

Demonstration of polycrystalline thin film coatings on glass for spin Seebeck energy harvesting

“…Thus, S SSE was simulated for various values of g r , where this relationship was found to agree well with the experimental data when λ SD = 2 nm, consistent with values reported for Pt at room temperature [21]. Whilst in general, an increase in S SSE with decreasing thickness is a result of the increasing resistivity of the PM layer, for t PM < 3 nm the reproducibility of the measurements deteriorated (as might be expected from the sensitive impact of the interface condition on the measurement) [23]. It would be expected that the impact of producing polycrystalline films can lead to variations in the interface quality (with regards to spin conversion [22] and thermal resistance [24]) between samples and across the device surface (parameterised by g r ), as shown by the simulations in Fig.…”

Spin‐thermoelectric voltage in longitudinal SSE elements incorporating LPE YIG films and polycrystalline YIG slabs with an ultrathin Pt layer

“…Here the S SSE of unannealed slab elements is less than half that of annealed elements. As regards the annealing effect on sintered polycrystalline YIG plates, S SSE is assumed to increase with the improvement of spin mixing conductance due to recrystallization on YIG slab surfaces through annealing . Strong hysteresis was observed in the V STE loops of unannealed and annealed polycrystalline slabs as shown in Figure B; the V STE ‐ H hysteresis observed by Uchida et al in sintered polycrystalline (Mn,Zn)Fe 2 O 4 slab elements was very similar to that observed in this study in the unannealed polycrystalline slab.…”

Spin Seebeck Power Conversion

“…The longitudinal SSE as detected by the ISHE converts thermal energy into electric power that is proportional to the sample area and therefore does not require complicated thermopile structuring. It is attractive for applications in large-area thermoelectric power generators that are made by simply coating suitable substrates [36], [48].…”

“…The spin current pumped out of the ferromagnet into a normal metal reads [18], [68] e J sp σ =h 4π G r m ×ṁ + G iṁ (48) where m is the magnetization direction at the interface, · · · is a time or ensemble average, and G r /G i is the real/imaginary part of the spin mixing conductance, which determines the magnitude of the pumped spin current [7] in units of −1 .…”