The objective of this program is to develop and study the characteristics of microwave magnetic auto-oscillators driven by pure spin currents. The intellectual merit is a deeper understanding of phenomena induced in nanoscale magnetic systems by spin currents, which will be facilitated by the new, previously inaccessible structures and geometries of devices driven by spin currents, by the development of advanced magnetic characterization techniques - micro-focus Brillouin Light Spectroscopy and x-ray dichroism microscopy, and by the advances in theoretical understanding of nanoscale magnetic systems. The broader impacts are enhanced competitiveness of US science/technology, training of specialists for the electronics industry, and general public education. Namely, a new class of microwave auto-oscillators developed in this program will help maintain US leadership in microwave electronics. Undergraduate and graduate students will be exposed to the modern methods of fabrication and characterization of spintronic nanostructures, and will interact with the leading scientists. Outreach activities including lectures and demonstrations on nanoscience and nanotechnology tailored for K-12 teachers and students will scientifically inform the general public. Student education will be enhanced through the incorporation of theoretical and experimental methods of nanotechnology and spintronics into the graduate and undergraduate curricula. The main transformative aspect of the proposal will be the development of a qualitatively new type of active spin-based devices where spin currents will be used directly, without being accompanied by charge currents, opening the possibilities for using new types of materials and device geometries.