UC San Diego

Multiferroic magnetoelectric composites are an attractive material system for multifunctional design due to their ability to bidirectionally couple magnetic and electric fields at nearly all length and time scales. Unfortunately, all efficient multiferroic composites have been reliant on stiff, brittle, and sometimes lead-based materials, which inhibits their implementation to wearable, biomedical, and soft robotic applications. Many prior soft and semi-organic multiferroic composites have been investigated and reported in literature, however they fall orders of magnitude short to their stiff and brittle counterparts. Thus, the objective of this project is to develop a novel class of soft semi-organic or completely organic multiferroic composites with considerable magnetoelectric coupling. The hypotheses of the proposed research is based on overcoming two engineering shortcomings of the prior semi-organic multiferroic research; namely the poor magnetostriction and property-mismatch arbitration. Therefore, two classes of composite materials are proposed which aim to replace the poorly performing ferromagnetic materials in prior studies with 1) giant magnetostrictive rare-earth alloy particulates or 2) newly discovered organic magnetic polymers. The composites were fabricated, analyzed, and characterized through computational and experimental techniques, including finite element analysis, explicit dynamic modeling, probe force microscopy, magnetometry, crystallography, dynamic mechanical analysis, dielectric analysis, terahertz and infrared spectroscopy, and other various testing methods. The culmination of the characterization techniques produces comprehensive property maps of these two composites which elucidates pitfalls and enlighten scientific foundations of how each material can beneficially or detrimentally affect the other. Results show the feasibility of these composites to fill various applications and illuminates a path for future studies to take soft multiferroic composites even further.