Abstract

The problem of spin current generation and transformation into electric signals in thin-film ferromagnet/nonmagnetic metal bilayer structures is investigated. This direction is of considerable scientific interest and promising for applications in spintronics. An LSMO/Pt structure consisting of an epitaxial film of ferromagnetic manganite La_2/3Sr_1/3O₃ grown on a single-crystal NdGaO₃ substrate and coated with a platinum film has been studied experimentally. The spin current was generated by the spin pumping method upon the excitation of a ferromagnetic resonance in the ferromagnetic layer and was detected by the electric voltage U^SP arising in the nonmagnetic metal layer due to the inverse spin Hall effect. Owing to its relatively low Curie temperature (~350 K), using LSMO allowed the influence of ferromagnetic-layer magnetization on the spin current generation to be studied in detail in the temperature range 100–350 K. In this case, the influence of the shape of the ferromagnetic resonance line, which is the convolution of homogeneous (Lorentzian) spin packets and inhomogeneous Gaussian broadening (Voigt model), was consistently taken into account. As a result of our analysis of all the parameters defining U^SP, we have obtained the temperature dependence of the mixed spin conductance, which has turned out to be approximately proportional to the ferromagnet magnetization squared. This result is compared with existing theoretical models.

中文翻译：

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磁化强度对铁磁-常态金属双层结构中自旋泵浦效率的影响

摘要

研究了薄膜铁磁体/非磁性金属双层结构中自旋电流的产生和转换为电信号的问题。该方向具有相当大的科学兴趣，并有望在自旋电子学中得到应用。实验研究了由在单晶NdGaO ₃衬底上生长并涂有铂膜的铁磁锰矿La _2/3 Sr _1/3 O ₃的外延膜组成的LSMO / Pt结构。通过在铁磁层中激发铁磁共振而通过自旋泵浦法产生自旋电流，并通过电压U ^SP来检测自旋电流。由于逆自旋霍耳效应而在非磁性金属层中产生。由于其居里温度较低（〜350 K），因此使用LSMO可以在100–350 K的温度范围内详细研究铁磁层磁化强度对自旋电流产生的影响。一贯考虑到铁磁共振线的形状，即均匀（洛仑兹）自旋包和不均匀高斯展宽（Voigt模型）的卷积。作为我们对定义U ^SP的所有参数的分析的结果，我们获得了混合自旋电导的温度依赖性，事实证明它与铁磁体磁化强度平方成正比。将该结果与现有理论模型进行比较。