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

TL;DR

This paper introduces a shapeable planar Hall sensor on a flexible substrate that maintains stable magnetic sensitivity under bending, stress, and strain, enabling multifunctional sensing for robotics.

Contribution

It presents the first planar Hall sensor that remains stable under mechanical deformation, combining magnetic and stress sensing capabilities on a flexible platform.

Findings

Stable magnetic sensitivity under bending and stress.

Independent planar Hall sensitivity from stress and strain.

Potential for multifunctional tactile sensing in robotics.

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.