Spin currents and domain wall dynamics based on the spin Seebeck effect

最近发现的自旋塞贝克效应是指铁磁材料中由温度梯度引起的自旋电流和自旋积累。这一效应将自旋自由度与热学性质相结合，为自旋热电子的应用开辟了新的前景。在理论和实验的联合努力中，申请者将研究由热梯度引起的铁磁体中的自旋电流。我们将使用自旋模型模拟以及最先进的微磁框架，其中包括热力学方面，并将模拟结果与实验结果进行比较。将局部激光（脉冲）加热应用于磁性纳米和微观结构，以调整温度梯度。为了检测自旋积累，我们将使用逆自旋霍尔效应并设计结构来确定其符号，位置和起源。在下一步中，我们将通过模拟和测量壁的脱壳和传播特性来研究热自旋电流对受限畴壁的影响。目标包括更深入地了解热诱导自旋电流的起源和性质，并确定这些自旋电流对畴壁施加的扭矩。

The recently found spin Seebeck effect refers to a spin current and spin accumulation induced by a temperature gradient in a ferromagnetic material. This effect opens new perspectives for spin caloritronic applications, combining the spin degrees of freedom with caloric properties. In a joint theoretical and experimental effort the applicants will investigate spin currents in ferromagnets, induced by thermal gradients. We will use spin model simulations as well as a state-of-the-art micromagnetic framework, which includes thermodynamic aspects, and compare the simulation results with their experimental counterpart. Localized laser (pulse) heating applied to magnetic nano- and microstructures will be used to tailor the temperature gradients. To detect a spin accumulation, we will use the inverse spin Hall effect and engineer the structures to determine its sign, position and origin. In a next step we will investigate the inuence of the thermal spin currents on confined domain walls by simulating and measuring the depinning and propagation properties of the walls. Objectives include a deeper understanding of the origin and the nature of the thermally induced spin currents and a determination of the torques that these spin currents exert on the domain walls.