Voltage-tunable magnetic hysteresis and domain patterns by electrochemical reactions

通过电化学反应实现电压可调磁滞和磁畴模式

• 批准号: 400178764
• 负责人: Professorin Dr.-Ing. Karin Leistner
• 金额: --
• 依托单位: Professur Elektrochemische Sensorik und Energiespeicherung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/400178764?language=en
• 关键词: Voltage; tunable; magnetic; hysteresis; domain

The control over magnetic properties in thin films plays a pivotal role in a multitude of modern device proposals in the fields of spintronics and magnet-based fluidic lab-on-chip systems. The manipulation of magnetism by an external voltage is strongly discussed as an energy-efficient alternative to current-based approaches that suffer from Joule heating. Within the research field of voltage control of magnetism, the electrochemical (magneto-ionic) control of nanoscale magnetism is a rapidly emerging topic. Both large effects and non-volatile setting of magnetic states by an external voltage come within reach when exploiting electrochemical phase transformations in magnetic films.In the proposed project we want to investigate reversible electrochemical reactions for voltage-tuning the magnetic hysteresis and domains of metal/oxide films. We intend to use Fe- and Co-based magnetic thin films as electrodes and liquid electrolytes that enable enhanced electric field effects and high ionic mobility at the magnet/electrolyte interface. The role of structural, compositional and microstructural variations occuring through electrochemical transformations will be analyzed and correlated with magnetic property changes. We expect to identify the key influencing factors and the conditions for enhanced reaction layer thickness and high reversibility of the magneto-ionic reactions. We will strive for a tunable Fe or Co layer with non-volatile behavior, where the magnetic state can be set by a moderate voltage and small initial current. The combination of such tunable top layers with bottom layers exhibiting perpendicular magnetic anisotropy promises to exponentiate the variability of magneto-ionic effects. Ideally, reversible magneto-ionic spin reorientation will be achieved within several nanometers.To track local magnetic changes during polarization within the electrolyte, an electrochemical cell compatible with Kerr microscopy will be developed. This in situ Kerr microscopy setup promises to resolve, for the first time, the local effect of magneto-ionic reactions on magnetic domains when using liquid electrolytes. Magneto-ionic effects in patterned structures will be investigated for voltage-tunable stray field landscapes and domain wall traps.

薄膜磁性能的控制在自旋电子学和基于磁体的流控芯片实验室系统的众多现代器件方案中起着举足轻重的作用。通过外部电压对磁性的操纵作为一种节能的替代方案被强烈讨论，以电流为基础的方法遭受焦耳加热。在磁性电压控制的研究领域中，纳米级磁性的电化学（磁离子）控制是一个新兴的研究课题。当利用磁膜中的电化学相变时，外部电压对磁性状态的大影响和非易失性设置都是可以实现的。在提出的项目中，我们想要研究可逆电化学反应的电压调谐，磁滞和金属/氧化物薄膜的畴。我们打算使用铁和钴基磁性薄膜作为电极和液体电解质，以增强电场效应和在磁体/电解质界面处的高离子迁移率。通过电化学转化，将分析结构、成分和微观结构变化的作用，并将其与磁性能变化联系起来。我们期望找出影响反应层厚度和磁离子反应高可逆性的关键因素和条件。我们将努力获得具有非挥发性行为的可调谐铁或钴层，其中磁性状态可以通过中等电压和小的初始电流来设置。这种可调谐的顶层与底层的组合表现出垂直的磁各向异性，有望反映磁离子效应的可变性。理想情况下，可逆的磁离子自旋重定向将在几纳米内实现。为了跟踪电解液极化过程中的局部磁变化，将开发一种与克尔显微镜兼容的电化学电池。这种原位克尔显微镜装置有望首次解决使用液体电解质时磁离子反应对磁畴的局部影响。在电压可调的杂散场景观和畴壁陷阱中，将研究图案结构中的磁离子效应。