Printable giant magnetoresistive sensors with high sensitivity at small magnetic fields

在小磁场下具有高灵敏度的可印刷巨磁阻传感器

• 批准号: 407555984
• 负责人: Professor Dr.-Ing. Christoph Leyens
• 金额: --
• 依托单位: Institut für Ionenstrahlphysik und Materialforschung
• 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/407555984?language=en
• 关键词: Printable; giant; magnetoresistive; sensors; sensitivity

Printed electronics are about to revolutionize the field of conventional electronics offering low-cost, large area and high-throughput production. By adding a magneto-sensitive element to the family of printable electronics, we envision the realization of energy efficient contactless switches for intelligent packaging or postcards as well as smart and protective clothes (e.g., for firefighters, athletes) offering the in-cloth integrated navigation and position tracking modules. Although highly demanded, high-performance printable magnetic field sensors relying on giant magnetoresistive (GMR) effect are not available manly due to the lack in the fundamental understanding of the magnetoresistive effects in a GMR powder mixed with a polymeric binder solution.First proof-of-concept realizations of printable GMR sensors are reported by us. However, the optimization of the sensors is based on empirical approaches, which do not allow us to achieve strong sensor responses in the range of small magnetic fields, e.g. <10 mT as needed for the application in consumer electronics and wearables. It can well be that the performance of printed sensors in the small fields region is fundamentally limited by the randomization effects due to the electron transport through percolated GMR flakes. Alternatively, it can be that we do not understand the role of the size of the GMR flakes on the GMR response of printed sensors. Is there a limitation on the flake size when the GMR response will disappear due to the mechanical impact upon ball milling? What is the impact of the ball milling on the magnetic properties of the GMR powder? In this project we address these important fundamental issues, aiming to boost the performance of printed GMR sensors further. Our preliminary work indicates that the magnetron sputter deposition used to fabricate the GMR powder might be not optimal to achieve sensitivity at small magnetic fields. In this project, we will prepare GMR powder using complementary approaches: (i) magnetron sputter deposition and (ii) ion beam sputtering. In contrast to the magnetron sputter deposition, the ion beam sputtering allows to produce GMR multilayers revealing (i) the absence of hysteresis and (ii) superior linearity even at small magnetic fields. This performance is very attractive for the realization of high-performance flexible and printable magnetic field sensors. The fabrication of GMR stacks using ion beam sputtering is not as well established as using magnetron sputter deposition. Therefore, the fundamental understanding of the magnetization processes in ion-beam sputtered magnetic/nonmagnetic sandwiches is still lacking. We will close this gap and investigate what is the physical reason behind the experimentally observed remarkable linearity and absence of hysteresis of the GMR response down to small magnetic fields of GMR stacks prepared by ion-beam sputtering.

印刷电子即将彻底改变传统电子领域，提供低成本，大面积和高吞吐量的生产。通过将磁敏元件添加到可印刷电子产品家族中，我们设想实现用于智能包装或明信片以及智能和防护服（例如，用于消防员、运动员），提供内置导航和位置跟踪模块。虽然高要求，高性能的可印刷的磁场传感器依赖于巨磁阻（GMR）效应是不是主要由于缺乏在与聚合物粘合剂solution.First概念验证实现的可印刷的GMR传感器混合的GMR粉末的磁阻效应的基本理解。然而，传感器的优化是基于经验方法，这不允许我们在小磁场范围内实现强传感器响应，例如消费电子和可穿戴设备中应用所需的<10 mT。印刷传感器在小场区域中的性能很可能从根本上受到由于电子传输通过掺杂的GMR薄片而引起的随机化效应的限制。或者，可能是我们不理解GMR薄片的尺寸对印刷传感器的GMR响应的作用。当GMR响应由于球磨时的机械冲击而消失时，是否对薄片尺寸有限制？球磨对GMR粉末的磁性能有什么影响？在这个项目中，我们解决这些重要的基本问题，旨在进一步提高印刷GMR传感器的性能。我们的初步工作表明，用于制造GMR粉末的磁控溅射沉积可能不是最佳的，以实现在小磁场下的灵敏度。在这个项目中，我们将使用互补的方法制备GMR粉末：（i）磁控溅射沉积和（ii）离子束溅射。与磁控溅射沉积相反，离子束溅射允许产生GMR多层膜，揭示了（i）不存在滞后和（ii）即使在小磁场下也具有上级线性。这种性能对于实现高性能柔性和可印刷的磁场传感器非常有吸引力。使用离子束溅射的GMR叠层的制造不如使用磁控管溅射沉积的那么完善。因此，对离子束溅射磁/磁夹层结构的磁化过程的基本理解仍然缺乏。我们将关闭这一差距，并调查什么是背后的实验观察到显着的线性和GMR响应的滞后下降到小磁场的GMR堆栈离子束溅射制备的物理原因。