磁性薄膜中自旋相关热输运的內禀机制研究

如何高效产生自旋流是当前自旋电子学面临的一个挑战性课题。最近，利用自旋塞贝克效应产生自旋流取得了许多成果，但有许多基本问题没有解决，包括自旋流在薄膜中是如何传播的，以及温度梯度和自旋波对自旋流的影响等。本项目将深入研究磁性结构中自旋塞贝克效应的自旋相关热输运的物理机制。首先，利用溅射和微加工技术制备磁性金属(NiFe)和绝缘体(YIG)微结构样品，通过测量样品在平面和垂直温度梯度下由于自旋塞贝克效应产生的电动势来确认自旋流的产生，然后，利用高精度的共聚焦扫描布里渊光散射技术来测量样品中的自旋波特性，系统分析其振幅和频率随温度梯度与磁场的变化关系，研究自旋流的产生对自旋波进动的影响规律，进一步深入理解自旋塞贝克效应和逆自旋霍尔效应的物理机制，最终实现高效产生、控制自旋流。

To generate pure spin currents effectively is a challengeable work for spintronics. Recently, there is lot of progress has been made in the field of spin Seebeck effect. However, some key aspects remain poorly known. For example, how the spin current transports in the magnetic/nonmagnetic film? What is the real inluence of the temperature gradient? In this study, we will investigate the physical mechanism of the intrinsic spin dedendent thermal transport in the magnetic structure. Firstly, the metallic(NiFe) and insulating magnetic (YIG) samples will be prepared by magnetron sputtering and lithorgraphy techniques. Via the inverse spin hall effect, the spin currents can be generated with the sample assigned with a in-plane or a out-of-plane temperature gradient. This is the so called Spin Seebeck effect, and can be confirmed by the voltage measurements across the sample. Secondly, the spin wave characteristics of the magnetic structure will be investigated by the method of the micro scanning BLS spectroscopy in order to find the interaction between spin currents and spin waves. The influence of the magnetic field and temperature gradient on the intensity and frequency of spin waves will be explored systematically. Thereafter, the intrinsic spin dependent thermal transport will be determined along with the method to effectively generate spin currents.