MR Sensors and applications
INESC MN is at the forefront of innovation in MR sensing devices for well established industrial sectors and new applications.
Reviews:
J Phys D: Appl Phys 50 (2017) 213001 |Proceedings of the IEEE 104 (2016) 1894
Eur Phys J Appl Phys 72 (2015) 10601 | J Phys: Cond Mat 19 (2007) 165221
Mapping Surface Defects
Industries have a strong pressure to reinforce the reliability and the safety of their products, while improving their profit and productivity. Non-destructive testing (NDT) meets this challenge gathering methods to provide information on the health of a structure without impairing its future usefulness. Among the NDT existing methods, Eddy current testing ensures the detection of surface flaws and buried defects in conductive materials requiring simpler sample preparation methods.
The method requires a broad range of operating frequencies (hundreds of Hz to MHz) that limits the use of conventional inductive sensors in a low frequency range. These limitations are surpassed by MR sensors due to their spatial resolution, high sensitivity and bandwidth. ECT reflection probes based on arrays of MgO-magnetic tunnel junctions have been applied in the inspection of surface and buried defects in conductive materials, being highlighted the evaluation of micrometric surface flaws in titanium alloys, which are characterized by an extremely low electrical conductivity.
IEEE Trans Mag 53 (2017) 6200805
IEEE Trans Mag 50 (2014) 6201304
Tactile sensors for robotics
Tactile sensing is a pivotal part of the development of intelligent robots, allowing such machines to feel the surrounding environment, and providing crucial support for the execution of most robotic tasks. Thus, providing technologies that are both sensitive while being significantly sturdy for everyday interaction with the environment becomes key. INESC MN has developed solutions involving extremely sensitive and fast MR sensors to detect the magnetic field generated by elastic polymers with embedded magnetic materials, therefore being able to transduce polymer deformation into an electrical quantity and consequently quantify the applied force. Our MR force sensors have been able to detect in the order of hundreds of µN up to several N, with designs inspired on human and insectoid tactile sensing structures.
IEEE Rob Autom Let 2 (2017) 971
IEEE Trans Mag 53 (2017) 4700205