标题： 绝缘铁磁-反铁磁-铁磁三明治层中的自旋输运随温度的变化 显示英文标题

标题： Spin transport in an insulating ferrimagnetic-antiferromagnetic-ferrimagnetic trilayer as a function of temperature

摘要： 我们研究了在宽温度范围内，绝缘铁磁-反铁磁-铁磁三明治结构中热生成自旋电流的输运特性。 在钇铁石榴石（YIG）YIG/NiO/YIG三明治结构上，利用铂（Pt）中的逆自旋霍尔效应检测了由自旋塞贝克效应（SSE）产生的自旋电流。 通过研究不同NiO厚度的样品，确定了室温下NiO的自旋扩散长度为4.2纳米。 有趣的是，在30 K以下，逆自旋霍尔信号与GGG基板有关。 信号的场依赖性在低温下符合S=7/2自旋（$\mathrm{Gd^{3+}}$）的布里渊函数。 在低场下的SSE信号出现尖锐变化是由于YIG磁化强度的切换。 在约100 K处观察到了SSE响应的宽峰，我们认为这与YIG中自旋扩散长度的增加有关。 这些观察结果对于理解通过磁绝缘体生成和输运自旋电流的特性以及顺磁基板在自旋电流生成中的作用具有重要意义。 显示英文摘要

摘要： We present a study of the transport properties of thermally generated spin currents in an insulating ferrimagnetic-antiferromagnetic-ferrimagnetic trilayer over a wide range of temperature. Spin currents generated by the spin Seebeck effect (SSE) in a yttrium iron garnet (YIG) YIG/NiO/YIG trilayer on a gadolinium gallium garnet (GGG) substrate were detected using the inverse spin Hall effect in Pt. By studying samples with different NiO thicknesses, the NiO spin diffusion length was determined to be 4.2 nm at room temperature. Interestingly, below 30 K, the inverse spin Hall signals are associated with the GGG substrate. The field dependence of the signal follows a Brillouin function for a S=7/2 spin ($\mathrm{Gd^{3+}}$) at low temperature. Sharp changes in the SSE signal at low fields are due to switching of the YIG magnetization. A broad peak in the SSE response was observed around 100 K, which we associate with an increase in the spin-diffusion length in YIG. These observations are important in understanding the generation and transport properties of spin currents through magnetic insulators and the role of a paramagnetic substrate in spin current generation.