学术预告|郭硕鸿讲座 (第四十六期)| 磁性传感器：从超薄薄膜生长到意外系统中的传感器集成

    Nanoelectronics combines physical principles of materials with the impressing capability of engineering ultra-small devices at the nanoscale. Magnetic field sensors - in particular, magnetoresistive MR sensors, were driven by the technological push from computers and information storage in the early 1990’s. Presently they have a mature and transversal level of implementation in the market, from automotive to biomedical domains. In this talk, I will first introduce key concepts in spintronics and highlight the physics mechanisms defining the sensor performance and the figures of merit for the classification of an outstanding MR sensor. The impressive technological progress in thin film preparation and characterization, combined with nano-microfabrication tools offer presently large spectra for device design. The materials discussed include several varieties of thin films: oxide films as tunneling barriers, ultrathin amorphous and crystalline films, ultrathin textured layers with grain size control, magnetically soft layers or antiferromagnetic films – all combined onto multilayer stacks, typically thinner than 60nm in total. In addition, the noise mechanisms (the “killing factor” that limits the MR sensor performance) will be discussed, and I will show successful strategies for improving the signal-to-noise ratio, improving the ultimate field detectable by an MR sensor.

    Examples where spintronic sensors are useful tools for precision sensing will be provided, including integration with microfluidics, optical and MEMS micromachined actuators. The detection principles, sensor design, simulations and experimental validation will be discussed for exciting applications where MR sensors bring added value over other competing technologies. During my talk, I will show how challenging applications have identified creative solutions, requiring joint skills in transversal areas as physics, materials, electronics and mechanical engineering. I expect academics and engineers to be encouraged to propagate their expertise in magnetism to the young, talented people we see every day, so to trigger innovation in future spintronic sensors.

    Susana Cardoso de Freitas于2002年在葡萄牙里斯本大学和葡萄牙微系统与纳米技术研究所取得物理学博士学位。在2002年，她担任美国IBM（国际商用机器公司）T.J.沃特森研究中心前期专业工程师，之后成为葡萄牙微系统与纳米技术研究所研究员。她现在是该研究所自旋电子学和磁性生物传感器研究组组长。她作为首席研究员，在发展先进材料、传感器、和集成系统的合作项目上有大量的经验。在2018年，她被选为100位葡萄牙“女性科学家”之一。作为物理系的副教授，她负责学生合作和在纳米电子学，微细加工技术和自旋电子学的高级培训。她是超过300篇论文，25个章节的合著者。她有5项专利，管理几项与全世界磁场感应器产业相关的技术合同。