Omnidirectionally Stretchable Spin-Valve Sensor Array with Stable Giant Magnetoresistance Performance

Flexible magnetic sensors, which have advantages such as deformability, vector field sensing, and noncontact detection, are an important branch of flexible electronics and have significant applications in fields such as magnetosensitive electronic skin. Human skin surfaces have complicated deformations, which pose a demand for magnetic sensors that can withstand omnidirectional strain while maintaining stable performance. However, existing flexible magnetic sensor arrays can only withstand stretching along specific directions and are prone to failure under complicated deformations. Here, we demonstrate an omnidirectionally stretchable spin-valve sensor array with high stretchability and excellent performance. By integrating the modulus-distributed structure with liquid metal, the sensor can maintain its performance under complex deformations, enabling the overall system with omnidirectional stretchability. The fabricated spin-valve sensor exhibits a nearly unchanged giant magnetoresistance ratio of 8% and a maximum sensitivity of 0.93%/Oe upon omnidirectional strain up to 86% and can maintain stable performance without fatigue for over 1000 stretching cycles. Furthermore, this spin-valve sensor array is characterized by stable sensing performance for magnetic fields under complicated deformations and can be applied as a magnetosensitive electronic skin. Our results provide insights into the development of next-generation stretchable and wearable magnetoelectronics.