Functional Materials and Device Concepts for Magnetic Sensing, Gas Detection and Energy Harvesting

This cumulative thesis investigates three areas of materials science and physics: magnetic-field sensing, energy harvesting, and gas detection. Although examined separately, they are linked by their potential integration into self-sustaining sensor platforms for Internet of Things (IoT) applications, amid growing demand for sensing systems in industrial, environmental, and biomedical fields. The first part addresses passive, highly sensitive magnetic-field sensors for low-power and biomagnetic applications. Two magnetoelectric (ME) concepts are presented. The first combines flexible, tunable magnetostrictive polymer composites with an electret to form a scalable capacitive sensor for low-field detection. The second avoids magnetostrictive materials by using permanent magnets to induce mechanical strain and piezoelectric transduction to generate the electrical signal. A third configuration combines both approaches, employing permanent magnets as the magnetic phase and an electret for signal generation. These devices were also evaluated as energy harvesters, the thesis’s second topic. In all configurations, magnetic-field variations generate electrical energy, enabling dual use as sensors and harvesters. The results demonstrate conversion of low-frequency ambient magnetic fields into usable electrical energy and confirm the potential of ME harvesters for passive, autonomous sensor nodes in embedded and distributed systems. The third part examines metal-oxide (MOX) gas sensors, whose resistance changes when semiconducting metal oxides interact with target gases. Nanostructuring, surface doping, and polymer functionalization are investigated to enhance sensitivity, selectivity, and humidity resistance. Particular emphasis is placed on tailoring surface interactions and optimizing responses to gases relevant to environmental monitoring, industrial safety, and biomedical diagnostics.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Christian-Albrechts-Universität zu Kiel

Year

2026

Author dc:creator

• Zimoch, Lukas

Contributors dc:contributor

• Adelung, Rainer
• Wulfinghoff, Stephan
• Wu, Wenzhuo

• Magnetoelectric sensors
• Magnetic-field sensing
• Energy harvesting
• Electret transducers
• Magnetostrictive polymer composites
• Metal-oxide gas sensors
• Polymer functionalization
• Internet of Things
• Functional Materials
• Nanostructured thin films

Repository record source_url

https://macau.uni-kiel.de/receive/macau_mods_00008804

OAI identifier oai:identifier

oai:macau.uni-kiel.de:macau_mods_00008804