This Small Business Innovation Research (SBIR) Phase I project will develop ordered arrays of surfactant-coated magnetic nanoparticles for application in Radio Frequency (RF) and spintronic devices. The advent of tools to fabricate 2-D arrays of nanoparticles has led to concerted efforts in the development of different methods to produce size and shape-controlled magnetic nanostructures. The incorporation of these nanostructures in functional devices however, requires a thorough understanding of the relationship between nanostructural parameters and electromagnetic performance. The lack of control over crucial parameters like particle size and separation drastically compromises reproducibility. The nascent class of ordered nanostructured materials circumvents this problem by offering control over nanoscale morphological parameters. The potential application in RF and spintronic devices has recently been identified. Monodisperse coated single domain magnetic nanoparticles will be synthesized, with precise control over size and coating thickness. Subsequent fabrication of ordered closepacked monolayer films will be via the Langmuir-Blodgett technique. A study of the spindependent tunneling and RF absorption and tuning characteristics will help understand the role of particle size in RFand spintronic device performance.<br/><br/>Arrays of surfactant-coated nanoparticles can be developed into spintronic devices for high-resolution magnetic sensing, vital to the high-density recording industry. When deposited on ferroelectric substrates, these arrays will provide dual tuning (magnetic and electrical) in devices like micro-patch antennas, phase-shifters, resonators etc.