Materials and Approaches to Eco-Sustainable Magnetoelectronics

Composites consisting of magnetic fillers in polymers and elastomers enable new types of applications in soft robotics, reconfigurable actuation and sensorics. In this presentation we will focus on the development of magnetic composites to realize solution processable and eco-sustainable magnetic field sensors. This functional electronic component is a currently missing member in the family of eco-sustainable electronics. In particular, we will present approaches to realize magnetic composites based on materials revealing high degree of spin polarization and electrical percolation, which result in printed magnetic field sensors [1,2]. First, we will review recent demonstrations of printed magnetoelectronics that can be stretchable, skin-conformal, capable of detection in low magnetic fields and withstand extreme mechanical deformations [3,4]. The use of Bi as a functional filler of a composite [3] acts as a green alternative to conventional environmentally polluting Ni-based sensors [4]. We show that printed Bi sensors reveal a linear nonsaturating magnetoresistive response, which is a fingerprint of the electronic band structure of the Bi material - a higher order topological insulator. We feature the potential of printed magnetic field sensors to turn any object into an interactive surface via the realization of a smart magnetosensitive wallpaper or in-mold magnetoelectronics [3]. We will introduce a technology to realize self-healable magnetic field sensors, which can be repaired upon mechanical damage, hence extending the life-time of magnetoelectronics and reducing the amount of toxic magnetic waste [5]. This opens new perspectives for magnetoelectronics in smart wearables, interactive printed electronics and motivates further explorations towards the realization of recyclable magnetoelectronics [6]. For the latter, we will discuss eco-sustainable, namely biocompatible and biodegradable magneto sensitive devices, which can help to minimise electronic waste and bring magnetoelectronics to new application fields in medical implants, health monitoring, and realization of self-aware soft-bodied robots [1].

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[3] E. S. Oliveros Mata et al., Dispenser printed bismuth-based magnetic field sensors with non-saturating large magnetoresistance for touchless interactive surfaces. Adv. Mater. Technol. 7, 2200227 (2022).
[4] M. Ha et al., Printable and stretchable giant magnetoresistive sensors for highly compliant and skin-conformal electronics. Adv. Mater. 33, 2005521 (2021).
[5] R. Xu et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Communications 13, 6587 (2022).
[6] X. Wang et al., Printed magnetoresistive sensors for recyclable magnetoelectronics. J. Mater. Chem. A 12, 24906 (2024).