by Prof. Dr. Paulo Freitas, International Iberian Nanotechnology Laboratory, Braga, Portugal
14.02.2019, 17:00 h, TF, Seminar room C-SR 1
Spintronic sensors are being used for a variety of applications from read heads in hard disks and memory elements in MRAM cells, to current, position (linear and angular), and magnetic field sensors used in automotive, a variety of industrial, and more recently in biomedical/biosensor applications1,2,3. These magnetoresistive sensors can be integrated over CMOS in a back end process (MRAM and monolithic sensors). For most applications, S/N at the relevant frequency of operation (from DC to GHz), thermal stability ( of the various magnetic layers in the stack), voltage output, determine the type of sensor to be used. Typical GMR/TMR individual sensors with micron size features reach detectivities down to few nT at low frequencies (10Hz). When connected in arrays, S/N can be improved by SQR N. Soft flux guides can also be used (gain up to few hundred). With these architectures detectivities down to 10 -100pT at 10Hz can be reached. These sensors can also be fabricated in flexible polyimide substrates if required keeping standard characteristics, as well as be integrated in MEMS structures as cantilevers and microneedes. Examples of applications in the biomedical area will be given (protein or DNA integrated biochip platforms, integrated cytometers use for cell/bacteria separation and enumeration, magnetrodes used for neural magnetic field recording).
1 “Spintronic Sensors”, P.P.Freitas, R.Ferreira and S.Cardoso, Proceedings of the IEEE, 104 (10), pp. 1894 - 1918 (2016); 10.1109/JPROC.2016.2578303
2 “Challenges and trends in magnetic sensor integration with microfluidics for biomedical applications”,S.Cardoso, D.Leitao, T.Dias, J.Valadeiro, M.Silva, A.Chicharo, V.Silverio, J.Gaspar and P.P.Freitas, Journal of Physics D-Applied Physics, 50 (21), 213001 (2017); https://doi.org/10.1088/1361-6463/aa66ec
3 “Lab-on-Chip Devices: Gaining Ground Losing Size”, V.C. Romao, S. A. M. Martins, J.Germano, F. A.Cardoso, S.Cardoso, P.P. Freitas, ACS Nano 11 (11), pp 10659–10664 (2017); DOI: 10.1021/acsnano.7b06703