Figure 4: Observation of plasmonic spin pumping.

(a) λ dependence of the light transmittance of the Pt/BiY₂Fe₅O₁₂/Au-NP and Pt/BiY₂Fe₅O₁₂ samples. The samples were prepared at the same time. (b) λ dependence of the electric voltage between the ends of the Pt layer normalized by the incident light power, V/P, in the Pt/BiY₂Fe₅O₁₂/Au-NP and Pt/BiY₂Fe₅O₁₂ samples, measured when H of H=200 Oe was applied along the x or y direction. The in-plane coercive force of the BiY₂Fe₅O₁₂ layer is around 30 Oe; the magnetization of BiY₂Fe₅O₁₂ is aligned along the H direction at H=200 Oe. The position of the SPR wavelength is marked with a red arrow. A blue solid curve was obtained by fitting the observed peak voltage structure using a Gaussian function. The error bars represent the s.d. of the measurements. (c) P dependence of V in the Pt/BiY₂Fe₅O₁₂/Au-NP sample at λ=690 nm and 500 nm, measured when H of H=200 Oe was applied along the x direction. (d) H dependence of V/P in the Pt/BiY₂Fe₅O₁₂/Au-NP sample for various values of λ (=760, 740,..., 400 nm), measured when H was along the x direction. The scale bar represents V/P=20 × 10⁻⁶ V W⁻¹. The dark blue and black lines (light blue and grey lines) show the V/P signals measured when H was swept from positive to negative (from negative to positive).