Piezoelectric Component in 2-2 magnetoelectric sensors

由磁致伸缩相和压电相组成的磁电（ME）复合材料有望用于医疗应用的非制冷非屏蔽磁场传感器。磁电效应的幅度和信噪比（SNR）尤其取决于压电特性和电极配置的产品特性。在本项目中，将评估和开发措施，以进一步增加磁电效应的幅度和通过压电元件的变化的信噪比。因此，磁电磁场传感器的检测极限应进一步降低。在这样做的三个部分方面将密切合作的建模（Gerken）和实验（Quandt）进行检查。在第一个领域ME薄膜传感器，利用叉指电极将进行研究。通过将叉指电极用于薄膜传感器，可以实现更高的信号强度。同时，由于较低的电容，观察到噪声水平的增加。在这里，系统的实验研究的影响，设计变化（最大。电极间距、电极布局、膜厚度、衬底厚度）和电参数（极化、电容、噪声分量），并开发SNR的详细模型。在第二个领域中，将探索BCZT膜的使用。沿着法律要求的避免铅的重要方面，这些膜相对于PZT膜可显示出进一步的效果增加。为此，必须建立通过化学溶液沉积（CSD）或通过在晶片级上的磁控溅射的大面积膜沉积。将探讨这种大面积沉积的必要条件。由于这些无铅铁电体将与叉指电极结合使用，因此需要找到BCZT薄膜的氧化和绝缘种子层。这些薄膜将与也使用叉指电极的PZT薄膜以及已经开发的平板电容器配置中的低损耗AlN薄膜进行比较。作为第三个领域，将研究在一个传感器中使用多个压电元件。通过分离磁致应变的影响，预期减少由于声信号和振动引起的交叉灵敏度。至于该项目的磁电复合材料，使用标准磁致伸缩材料（例如FeCoSiB膜）或项目P2的新型的、性能增强的多层膜。本项目取得的成果将进入项目P4、P9、P10。

Magnetoelectric (ME) composites composed of a magnetostrictive and a piezoelectric phase are promising for uncooled unshielded magnetic field sensors for medical applications. The amplitude of the magneto electric effect and the signal-to-noise ratio (SNR) depend, among others, as a product property on the piezoelectric properties and the electrode configuration. In this project measures are to be evaluated and exploited in order to further increase the amplitude of the magneto electric effect and the signal-to-noise ratio by variation of the piezoelectric component. As a consequence the limit of detection of the magneto electric magnetic field sensors should be further lowered. In doing so three partial aspects will be examined in close collaboration of modelling (Gerken) and experiments (Quandt). In the first area ME thin-film sensors utilizing interdigital electrodes will be studied. By employing interdigital electrodes for the thin-film sensors, higher signal strengths can be achieved. At the same time, due to lower capacitance, an increase in the noise level is observed. Here systematic experimental studies of the influence of design variations (max. electrode spacing, electrode layout, film thickness, substrate thickness) and electrical parameters (poling, capacitance, noise components) are to be carried out and a detailed model of the SNR developed. In the second area the usage of BCZT-films will be explored. Along with the important aspect of legally required lead avoidance, these films may show a further effect increase with respect to PZT-films. For this a large-area film deposition either by chemical solution deposition (CSD) or by magnetron sputtering on wafer level, has to be established. The necessary conditions for such a large-area deposition will be explored. As these lead-free ferroelectrics will be employed in combination with interdigital electrodes, oxidic and insulating seed layers for BCZT-films need to be found. A comparison of these films will be performed with PZT-films which also employ interdigital electrodes and with already developed, low-loss AlN-films in plate capacitor configuration. As third area the usage of multiple piezoelectric components in one sensor is to be investigated. By separation of the effect of magnetically induced straining, a reduction of cross-sensitivities due to acoustic signals and vibrations is anticipated. As for the magneto electric composites of this project, either standard magnetostrictives (e.g. FeCoSiB-films) or novel, property enhanced, multilayer films of project P2 are used. The results obtained in this project will enter the projects P4, P9 and P10.