In this study, we develop a permanent magnet capable of withstanding high loads (~2 kN) and large displacements (~50% compressive deformation). This magnet can be used to develop a battery‐free Internet of Things device. To investigate the power generation mechanism, we build a custom compressible vibrating sample magnetometer (VSM) and examine magnetization changes during compression. X‐ray computed tomography (CT) scans and image analysis are also employed. The developed permanent magnet foamed urethane elastomer (PMFUE) is fabricated by dispersing neodymium particles in a tough foamed urethane elastomer, which is then molded and magnetized. Deformation‐induced magnetization changes (inverse magnetostriction) enable power generation under high‐load, large‐displacement, and low‐frequency vibration, allowing wireless transmission. VSM measurements show that magnetization doubles at 50% compression compared to that at 0% compression. X‐ray CT scans reveal that despite significant volume reduction, the internal particles barely rotate, explaining the observed effect. These findings show that volume reduction and minimal particle rotation cause dramatic changes in magnetic moment density, triggering the inverse magnetostriction effect. This mechanism could advance the development of durable magnetostrictive materials and their application in vibration energy harvesting.
Oe et al. (Thu,) studied this question.