Dr. Susana Cardoso de Freitas of INESC Microsystems & Nanotechnologies, Instituto Superior Técnico, Universidade de Lisboa

Nanoelectronics combines physical principles of materials with the impressive 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 1990s. Currently, they have a mature and broad 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 physical mechanisms defining sensor performance and the figures of merit for the classification of outstanding MR sensors. The impressive technological progress in thin film preparation and characterization, combined with nano- and microfabrication tools, offer a large spectrum 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, and antiferromagnetic films, all combined onto multilayer stacks, typically thinner than 60 nm in total. In addition, the noise mechanisms (the “killing factor” that limits MR sensor performance) will be discussed, and I will show successful strategies for improving the signal-to-noise ratio, which determines 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 micro-electromechanical micromachined actuators. Detection principles, sensor design, simulations, and experimental validation will be discussed for exciting applications where MR sensors bring added value over competing technologies. I will show how challenging applications have inspired creative solutions, requiring joint skills in physics, materials, electronics, and mechanical engineering. I hope that academics and engineers will be encouraged to propagate their expertise in magnetism to the young, talented people we see every day, and so promote innovation in future spintronic sensors.

Biography:

Susana Cardoso de Freitas graduated in Technological Physics Engineering from the Instituto Superior Técnico (IST) Lisboa in 1996 and received the Ph.D. degree in Physics at the Universidade de Lisboa and INESC–MN in 2002. In 2002 she was a Co-Op Pre-Professional Engineer at the IBM T. J. Watson Research Center (USA), and then became a researcher at INESC-MN, where she is currently the co-leader of the Spintronics and Magnetic Biosensors Group. Since 2002 she has coordinated and participated as principal researcher in several European Union and national projects, with a strong collaboration with industry in advanced materials, sensors, and integrated systems. Her research focuses on optimizing magnetic materials and device architectures for robotics, biomedical, and industrial applications. As an Associate Professor in the Physics Department, Instituto Superior Técnico Lisboa, she is responsible for student coordination and advanced training in nanoelectronics, microfabrication, and spintronics, with a strong component of experimental learning in a clean room. She was appointed Coordinator for educational activities of the IEEE Portugal section in 2015. In 2018 she was selected as one of 109 Portuguese “Women in Science” by the Portuguese Ministry of Science and Technology (Mulheres na Ciência, 2nd edition, Ciência Viva, 2019). Since 2019 she has been a member of the “Ambassador for Innovation” group at IST. In 2019 she was elected Associate Member Delegate to the European Physics Society (EPS) Council and is a member of the General Council of the European Magnetism Association (EMA) for 2021-2023. She is a co-author of more than 300 articles, 25 book chapters, and five patents, and manages several technology-transfer contracts with industry worldwide related to MR sensors.

Email:

Address:INESC Microsystems & Nanotechnologies, Rua Alves Redol, 9 -1, Lisbon, Portugal, 1000-029