New Directions for Organic Spintronics: Organic-Based Magnetic Heterostructures and Microwave Magnetodynamics

Ohio State University, The, Columbus OH

Investigators

Abstract

Nontechnical Description: The push towards "ubiquitous computing," the inclusion of small-scale and low-power computing devices in everyday objects ranging from appliances, to clothing, to packaging, has emerged as a new driver that is pushing information technology off the desktop (or the laptop) and into every aspect of our world. The study of organic electronics is playing a major role in this new paradigm due to the mechanical flexibility, low cost, and ease of manufacturing enabled by these materials. Early signs of the success of this approach can be found in the commercial development of flexible display technologies based on organic light-emitting diodes and organic thin film transistors. However, this new technology is currently limited by the lack of non-volatile organic memory elements, i.e. the ability for a device to remember what it has been doing once the power is turned off. This project focuses on addressing this gap through the development of organic-based magnetic materials and the devices enabled by them. It is focused on developing the new materials, new devices, and new fundamental understanding necessary to translate the potential of these organic-based magnets into a realistic complement to the optical and electronic functionality already demonstrated for organic electronics. In addition, this project serves as training ground for the next generation of young researchers that will drive this evolving technical revolution. Recent graduates of the PI's group have moved on to positions at Samsung, Intel and science policy institutes, and current training has been integrated with Ohio State University's Masters to PhD Bridge Program to enhance the diversity of our future STEM workforce. In its first two years of operation this Bridge Program has already increased the students from underrepresented minorities in the Department of Physics by 400%. Technical Description: This project extends the boundaries of organic electronics to include magnetic and spintronic functionality. This effort exploits recent scientific and technical breakthroughs to explore the growth of all-organic magnetic heterostructures and investigate the dynamic excitation of organic-based magnetic materials in two independent but correlated thrusts. In Thrust 1, work focuses on determining the structure-function relationship between the growth of organic-based magnets and their static and microwave-frequency magnetic properties. This work includes the growth of ferromagnet/non-magnetic bilayers, ferromagnet/non-magnet/ferromagnet heterostructures, and corrugated films with shape-induced in-plane magnetic anisotropy. Thrust 2 focuses on exploring dynamic excitations of these systems, including the investigation of electrically detected ferromagnetic resonance, ferromagnetic resonance driven spin pumping detected both via ferromagnetic resonance linewidth changes and inverse spin-Hall effect generated voltages, and spin-transfer torque based on the spin-Hall effect in high spin-orbit metals for ferromagnet/metal bilayers. Taken together, these two Thrusts are laying the foundation for a new conception of microwave-frequency organic spintronics and magnetoelectronics.