Magnetostrictive multilayers for magneto-electric sensors - layer structure and magnetic domains

该项目的重点是研究用于磁电2-2结构的新型磁致伸缩元件，重点是不同应用场景中高灵敏度磁场传感器的相关磁畴过程。在该项目中，将评估使用已知和新型磁性材料、材料组合以及制备优化磁电复合材料的替代方法的条件。为此目的，溅射磁性多层膜系统与高压磁系数将进行研究。除了有效磁性材料参数对磁电响应的影响外，微结构和相关磁畴结构的影响将是我们研究的核心，以实现传感器的低检测限。界面和静磁耦合现象被用来控制传感器的磁致伸缩相的行为。通过建模和空间分辨的磁表征方法，将实现对结构化磁电多层膜的功能相关的磁过程的理解。将消除通过所显示的巴克豪森噪声检测低频信号的已知限制。因此，例如，与交换偏置层相结合，将系统地研究新的层系统。重点分析了不同工艺参数对器件磁畴结构和传感器噪声的影响。从简单模型结构获得的基本知识将转移到技术传感器结构。此外，还将研究能够承受更高加工温度的创新材料组合。为了实现高热稳定性以及高压磁系数，将探索FeCo/TiN多层结构。此外，将研究具有最高灵敏度的传感器结构的替代方法。将开发高灵敏度磁电传感器的材料和物理基础。研究结果有望使2-2磁电复合材料的磁性能得到大幅度提高。

The focus of the project is research on novel magnetostrictive components for magneto-electric 2-2 structures with a strong emphasis on the relevant magnetic domain processes for highly sensitive magnetic field sensors in different application scenarios. Within the project, the conditions for the use of known and also new magnetic materials, material combinations, and alternative approaches for the preparation of optimized magneto-electric composites are to be evaluated. For this purpose sputtered magnetic multilayer film systems with high piezomagnetic coefficients will be investigated. In addition to the influence of the effective magnetic material parameters on the magneto-electric response, the influences of the microstructure and the associated magnetic domain structure will be central to our studies in order to achieve a low limit of detection for the sensors. Interfacial and magnetostatic coupling phenomena are used to control the behavior of the magnetostrictive phase of the sensors.Through modeling and spatially resolved magnetic characterization methods, an understanding of the functional relevant magnetic processes of structured magneto-electric multilayers will be achieved. Known limitations in the detection of low frequency signals through exhibited Barkhausen noise will be eliminated. Therefore, e.g. in combination with exchange biased layers, novel layer systems will be systematically investigated. A special emphasis of the research lies in the analysis of the influences of different processing parameters on magnetic domain structure and the corresponding sensor noise exhibited by the devices. Fundamental knowledge obtained from simple model structures will be transferred to technical sensor structures. Moreover, innovative material combinations that can withstand higher processing temperatures will be investigated. In order to achieve high thermal stability together with high piezomagnetic coefficients FeCo/TiN multilayer structures will be explored. Moreover, alternative approaches for sensor structures with highest sensitivity will be investigated. The material and physical foundations for highly sensitive magneto-electric sensors will be developed. The results of the research are expected to lead to 2-2 magneto-electric composites with greatly improved magnetic properties.