Thermally induced spin polarization

热致自旋极化

• 批准号: 257844649
• 负责人: Dr. Timo Kuschel, Ph.D.
• 金额: --
• 依托单位: Arbeitsgruppe Dünne Schichten und Physik der Nanostrukturen
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/257844649?language=en
• 关键词: Thermally; induced; spin; polarization

The present project 'Thermally induced spin polarization' is proposed within the second period of the SpinCaT priority programme. It is dedicated to alternative detection techniques for thermally induced spin currents and spin polarizations beyond the use of the inverse spin Hall effect in Pt, since it has been shown that proximity effect in Pt may induce parasitic effects. This affects the spin detection for example in longitudinal spin Seebeck effect (LSSE) measurements in metals, where the anomalous Nernst effect (ANE) is also present. These techniques to use are magnetooptic Kerr effect (MOKE), x-ray resonant magnetic reflectivity(XRMR), tunnel magnetoresistance (TMR) and spin Nernst magnetothermopower (SMTP) which will be tested by thermally induced spin currents generated by either spin Seebeck (SSE) or spin Nernst effects (SNE).In 12/2011 the applicant joined the group of Prof. Reiss in Bielefeld and started to investigate the SSE in nickelferrite (NFO) thin films and in permalloy thin films within the SpinCaT project. Together with his coworkers he studied ANE contributions for temperature-dependent SSE measurements for the longitudinal as well as for the transverse geometry (TSSE). The separation for LSSE and ANE was demonstrated as well as the separation of ANE and planar Nernst effect (PNE) from a vanishing TSSE as published in several publications. Further experiments like XRMR were started in order to test the proximity effect of Pt/NFO bilayers and a MOKE based vectorial magnetometry setup was built up in the last months.The present proposal is the first-time proposal for the applicant. It describes in detail, how SSE induced spin polarization will be detected by MOKE in Bi doped NFO and in CoFeTb/Cu/FM trilayers (FM=YIG, NFO, magnetite). The SNE will be shown in platinum films using MOKE, XRMR and TMR. Additionally, the thermally induced spin Hall magnetoresistance which is more correctly the spin Nernst magnetothermopower will be investigated. First experiments are in progress and promise very interesting results.As already in the first periode of the SpinCaT priority programme, this work will be done in close collaboration with partner groups from Garching, Regensburg, Mainz, Kaiserslautern, Osnabrück and Giessen.

本项目“热致自旋极化”是在SpinCaT优先计划的第二阶段提出的。它致力于替代检测技术的热诱导自旋电流和自旋极化的使用以外的反自旋霍尔效应在铂，因为它已被证明，在铂的邻近效应可能会引起寄生效应。这影响了例如在金属中的纵向自旋塞贝克效应（LSSE）测量中的自旋检测，其中还存在异常能斯特效应（ANE）。使用的这些技术是磁光克尔效应（MOKE），x射线共振磁反射率（XRMR），隧道磁阻（TMR）和自旋能斯特磁热功率（SMTP），这将通过自旋塞贝克（SSE）或自旋能斯特效应（SNE）产生的热感应自旋电流来测试。2011年，申请人加入了比勒费尔德的Reiss教授小组，并开始在SpinCaT项目中研究镍铁（NFO）薄膜和坡莫合金薄膜中的SSE。他与同事一起研究了ANE对纵向和横向几何形状（TSSE）随温度变化的SSE测量的贡献。LSSE和ANE的分离被证明，以及ANE和平面能斯特效应（PNE）与消失的TSSE的分离，如在几个出版物中发表的。为了测试Pt/NFO双层膜的邻近效应，开始了进一步的实验，如XRMR，并在过去几个月建立了基于MOKE的矢量磁测量装置。详细描述了如何在Bi掺杂的NFO和CoFeTb/Cu/FM三层（FM=YIG，NFO，磁铁矿）中通过MOKE检测SSE诱导的自旋极化。SNE将使用MOKE，XRMR和TMR在白金电影中显示。此外，我们还研究了热致自旋霍尔磁电阻效应，即自旋能斯特磁热电势。第一批实验正在进行中，并有望取得非常有趣的结果。正如SpinCaT优先计划的第一阶段一样，这项工作将与来自Garching，里根斯堡，美因茨，Kaiseraustern，Osnabrück和Giessen的合作伙伴小组密切合作。