Fabrication of yttrium-iron-garnet/Pt multilayers for the longitudinal spin Seebeck effect

Abstract

For longitudinal spin Seebeck effect (LSSE) devices, a multilayer structure comprising ferromagnetic and nonmagnetic layers is expected to improve their thermoelectric power. In this study, we developed the fabrication method for alternately stacked yttrium-iron-garnet (YIG)/Pt multilayer films on a gadolinium gallium garnet (GGG) (110) substrate, GGG/[YIG(49 nm)/Pt(4 nm)]${}_n$ ($n=$ 1 - 5) based on room-temperature sputtering and $ex$-$situ$ post-annealing method and we evaluated their structural and LSSE properties. The fabricated [YIG/Pt]${}_n$ samples show flat YIG/Pt interfaces and almost identical saturation magnetization $M_{\mathrm{s}}$, although they contain polycrystalline YIG layers on Pt layers as well as single-crystalline YIG layers on GGG. In the samples, we observed clear LSSE signals and found that the LSSE thermoelectric power factor (PF) increases monotonically with increasing $n$; the PF of the [YIG/Pt]${}_5$ sample is enhanced by a factor of $\sim 28$ compared to that of [YIG/Pt]${}_1$. This work may provide a guideline for developing future multilayerbased LSSE devices.

arXiv comment21 pages, 4 figures

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Cited by in corpus (4)

• Spin and spin current -- From fundamentals to recent progress
• Spin Seebeck Effect: Sensitive Probe for Elementary Excitation, Spin Correlation, Transport, Magnetic Order, and Domains in Solids
• Composition-tunable magnon-polaron anomalies in spin Seebeck effects in epitaxial Bi${}_x$Y${}_{3-x}$Fe${}_5$O${}_{12}$ films
• Absence of evidence of spin transport through amorphous Y${}_3$Fe${}_5$O${}_{12}$