Exploring the thermoelectric properties of normal/ferromagnetic interfaces using current heating techniques

使用当前加热技术探索普通/铁磁界面的热电特性

• 批准号: 198371013
• 负责人: Privatdozent Dr. Charles Gould
• 金额: --
• 依托单位: Lehrstuhl für Experimentelle Physik III
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/198371013?language=en
• 关键词: Exploring; thermoelectric; properties; normal; ferromagnetic

In this project we propose to study in detail the nature of thermoelectric phenomena at normal/ferromagnetic interface using current heating techniques to locally apply the heat gradient. Our material of choice for this work will be the ferromagnetic semiconductor (Ga,Mn)As for two reasons. First, an all semiconductor device is much more appropriate for the current heating techniques needed to measure the diffusive thermopower (distinct from the phonon drag) than would be metallic junctions, and second, as our preliminary work already shows, the strong spin orbit coupling in this material, which couples the magnetic properties to the density of states, leads to a rich phenomenology of thermopower. Our preliminary studies have, for example, already revealed a strong tunneling anisotropic magneto-thermopower in the thermoelectric Seebeck effect. We expect to find and explore in detail anomalous and anisotropic contributions in all the thermoelectric and thermomagnetic effects such as Nernst, Ettinghausen and Righi-Leduc. It should be emphasized that while (Ga,Mn)As is the ideal material for our investigations, the effects studied here are by no means confined to the realm of semiconductors, and indeed will be important in all magnetic materials, but in particular those with strong spin orbit coupling, such as for example, CoPt multilayers.

在这个项目中，我们建议使用当前的加热技术局部应用热梯度来详细研究法线/铁磁界面处热电现象的本质。我们在这项工作中选择的材料是铁磁半导体 (Ga,Mn)As，原因有两个。首先，全半导体器件比金属结更适合测量扩散热电势（与声子阻力不同）所需的当前加热技术，其次，正如我们的初步工作已经表明的那样，这种材料中的强自旋轨道耦合，将磁特性与态密度耦合在一起，导致了丰富的热电现象学。例如，我们的初步研究已经揭示了热电塞贝克效应中的强隧道各向异性磁热电势。我们期望详细发现和探索所有热电和热磁效应中的反常和各向异性贡献，例如能斯特、埃廷豪森和里吉-勒杜克。应该强调的是，虽然 (Ga,Mn)As 是我们研究的理想材料，但这里研究的效应绝不限于半导体领域，实际上在所有磁性材料中都很重要，但特别是那些具有强自旋轨道耦合的材料，例如 CoPt 多层材料。