Interfacing an organic semiconductor C₆₀ with a non-magnetic metallic thin film (Cu or Pt) has created a novel heterostructure that is ferromagnetic at ambient temperature, while its interface with a magnetic metal (Fe or Co) can tune the anisotropic magnetic surface property of the material. Here, we demonstrate that sandwiching C₆₀ in between a magnetic insulator (Y₃Fe₅O₁₂:YIG) and a non-magnetic, strong spin–orbit metal (Pt) promotes highly efficient spin current transport via the thermally driven spin Seebeck effect (SSE). Experiments and first principles calculations consistently show that the presence of C₆₀ reduces significantly the conductivity mismatch between YIG and Pt and the surface perpendicular magnetic anisotropy of YIG, giving rise to enhanced spin mixing conductance across YIG/C₆₀/Pt interfaces. As a result, a 600% increase in the SSE voltage (V_LSSE) has been realized in YIG/C₆₀/Pt relative to YIG/Pt. Temperature-dependent SSE voltage measurements on YIG/C₆₀/Pt with varying C₆₀ layer thicknesses also show an exponential increase in V_LSSE at low temperatures below 200 K, resembling the temperature evolution of spin diffusion length of C₆₀. Our study emphasizes the important roles of the magnetic anisotropy and the spin diffusion length of the intermediate layer in the SSE in YIG/C₆₀/Pt structures, providing a new pathway for developing novel spin-caloric materials.

中文翻译：

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通过界面有机半导体的巨大自旋塞贝克效应

有机半导体C ₆₀与非磁性金属薄膜（Cu或Pt）的界面产生了一种新颖的异质结构，该异质结构在环境温度下是铁磁性的，而其与磁性金属（Fe或Co）的界面可以调节各向异性的磁性表面性能材料。在这里，我们证明了将C ₆₀夹在磁性绝缘体（Y ₃ Fe ₅ O ₁₂：YIG）和非磁性强自旋轨道金属（Pt）之间可通过热驱动自旋塞贝克效应促进高效自旋电流传输（SSE）。实验和第一性原理计算始终表明，C ₆₀的存在大大降低了YIG和Pt之间的电导率不匹配以及YIG的表面垂直磁各向异性，从而提高了YIG / C ₆₀ / Pt界面的自旋混合电导率。结果，相对于YIG / Pt，以YIG / C ₆₀ / Pt实现了SSE电压（V _LSSE）的600％的增加。在YIG / C ₆₀ / Pt上，随着C ₆₀层厚度的变化，与温度相关的SSE电压测量结果还显示，在200 K以下的低温下，V _LSSE呈指数增长，类似于C ₆₀自旋扩散长度的温度演变。我们的研究强调了磁各向异性和YIG / C ₆₀ / Pt结构中SSE中间层的自旋扩散长度的重要作用，为开发新型自旋热材料提供了新途径。