Shapeable planar Hall sensor with a stable sensitivity under concave and convex bending

Abstract

A shapeable planar Hall sensor has been fabricated by lift-off a bilayer structure of NiFe(10 nm)/IrMn (8 nm) grown on a Kapton/PDMS substrate without using a buffer layer. The sensor exhibits a magnetic field sensitivity of 0.74 $\mu$V/Oe.mA and provides a stable response under repetitive ON/OFF experiments. The concave and convex bending measurements indicate that the AMR voltage of the sensor is very sensitive to the stress and strain. However, the planar Hall sensitivity is independent from them with a stable linear region and unchanged peak positions in the magnetic field axis. This type of behaviour has been observed for the first time in the planar Hall sensors. Therefore, this novel device can fulfill simultaneous multifunctional sensing of small magnetic fields, stress and strain. This makes it promising for tactile sensing applications in humanoid robotics.