Fabrication Of Yttrium-Iron-Garnet/Pt Multilayers For The Longitudinal Spin Seebeck Effect

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 a fabrication method for alternately stacked yttrium-iron-garnet (YIG)/Pt multilayer films on a gadolinium gallium garnet (GGG) (110) substrate, GGG/[YIG(49nm)/Pt(4 nm)](n) (n = 1-5) based on room-temperature sputtering and ex-situ post-annealing methods 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-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 similar to 28 compared to that of [YIG/Pt](1). This work may provide a guideline for developing future multilayer-based LSSE devices. Published by AIP Publishing.