Metglas Based Multi-Modal Sensing Employing Magnetostrictive and Triboelectric Properties

This work presents the development and investigation of a mechanomagnetic sensor with Metglas as the active layer for potential multimodal sensing applications. Along with the conventional bulk magnetostrictive properties of Metglas, surface charge retention based triboelectricity is investigated for the first time. The pristine Metglas exhibits a unique switch in its triboelectric polarity and converts from a tribo-positive to tribo-negative on annealing at 500 degrees C. Two hybrid devices, consisting of PVDF/Metglas/PTFE and PVDF/annealed Metglas/glass layers, are fabricated to quantify the dual triboelectric/ magnetoelectric output characteristics of Metglas. The two devices generate a peak output voltage of 0.75 V and 1 V at 60 kPa pressure. Applying a DC magnetic field of 4 kOe in addition to the applied pressure results in a significant increase in output voltage to 2 V and 2.25 V, respectively. Additionally, the device can produce an output voltage of 0.48 V when a time-varying magnetic field of 0.4 Oe is applied at 49.9 kHz and lead to a magnetic field sensitivity of 1.2 V/Oe and a limit of detection of 0.01 Oe.