UCLA

As electronic devices become more integrated in everyday life, there is an increasing necessity for miniaturization with exceptional efficiency. The use of tunable magnetic materials for information storage and transfer can meet this demand with many significant advantages over current technologies. The implementation of this science is contingent on optimizing the voltage control of magnetism (VCM), which has additional applications in healthcare and sensing. This work seeks to improve VCM in multiferroic composites and magnetoioics. In chapter 3 of this thesis, we report a straightforward and scalable synthesis of superparamagnetic cobalt ferrite nanoparticles that allows for precise size selection. The particles produced via this route also have remarkable size and shape uniformity, making them ideal for use in a strain-mediated multiferroic composite. In chapter 4 we advance fundamental understanding toward achieving unprecedented magnetic control in nanostructured Sm-Co magnets via electrochemical hydrogen charging. The structural and magnetic properties of SmCo5 and Sm2Co17, as well as the kinetics and thermodynamics involved in their hydrogenation, are documented for future work. Oxidation in air and in electrolyte is identified as a key challenge.