3D‐Printed Giant Magnetoresistive (GMR) Sensors Based on Self Compliant Springs

This work presents the development and characterization of 3D‐printed mechanically driven giant magnetoresistance (GMR) sensors using self‐compliant spring structures and piezoresistive materials. Fused deposition modeling 3D printing has been employed to fabricate sensors from conductive and magnetic polylactic acid composite materials, enabling low‐cost and highly customizable designs. Three sensor topologies were fabricated to optimize magnetoresistive and piezoresistive responses. Electromechanical and magnetic characterizations showed that the self‐compliant spring arm width influences the device mechanical stiffness, piezoresistive response, and magnetoresistive sensitivity. Sensitivities up to 0.34%/mm for piezoresistive sensors with a 3‐mm arm under direct mechanical deformation and 0.77%/mT for the magnetoresistive sensors with a 1‐mm arm were obtained, with a response 10 times higher in sensitivity than other printed spin‐dependent GMR devices in the literature. The applicability was demonstrated in pressure sensing and noncontact magnetic position detection, integrated in a Bluetooth low energy application. The sensors showcased reliable performance under dynamic conditions at a frequency range of 0.1, 0.25, and 0.5 Hz, highlighting their potential in automotive, robotics, and consumer electronics. This work establishes self‐compliant structural design as an effective tool for fabricating mechanically driven GMR‐like sensors using low‐cost, additive manufacturing techniques, allowing further integration of geometry‐driven devices into increasingly interconnected IoT networks.