Batch-fabrication and characterization of miniaturized axisymmetric electropermanent magnets

Abstract

This work describes the simulation, batch fabrication, functional demonstration, and magnetic field/force characterization of highly miniaturized ∼3.8 mm3 axisymmetric electropermanent magnets (EPMs). Two different bonded high-coercivity, rare-earth permanent magnet powders (∼15 μm Sm2Co17 particles and 6 μm NdFeB particles) were evaluated for the fabrication of the fixed magnets in the EPM, reaching latching force on/off ratios of 191:1 and 303:1 respectively. Compared to conventional side-by-side architecture, the axisymmetric design provides: 1) symmetric magnetic field along the magnetization axis, as opposed to the asymmetric fields in the typical transverse configuration, 2) higher and controllable latching force in a smaller volume, and 3) a path for further batch-microfabrication and system integration.