Asymmetric In-Plane Temperature Contribution in Longitudinal Spin Seebeck Effect Measurements in the Pt/WSe2/YIG Hybrid Structure

Abstract

We investigate the presence of asymmetric in-plane temperature contribution in longitudinal spin Seebeck effect (LSSE) measurements with an out-of-plane temperature gradient. This is performed by inserting ∼4-7 nm thick WSe2 films between the Pt and YIG layers, where WSe2 interlayers are wet-transferred with different surface coverages on YIG substrates. We observed an unintended in-plane Seebeck effect in the Pt/WSe2/YIG structure due to the asymmetric lateral temperature distribution during LSSE measurements. By applying out-of-plane temperature gradients in the Pt/WSe2/YIG structure, the modified in-plane Seebeck factor (∼ΔVa∥/ΔT⊥) was found to be ∼1.0-1.6 μV/K depending on the surface coverage of the WSe2 interlayer. Furthermore, the ratio of the effective in- and out-of-plane temperature differences (ΔTa∥/ΔT⊥) was found to be a maximum of ∼48.6%, indicating a substantially high in-plane temperature contribution in LSSE measurements. Our findings indicate that the in-plane temperature contribution can be substantial in the LSSE measurement in a Pt/YIG structure using two-dimensional interlayers. © 2021 American Chemical Society. All rights reserved.