Current-Driven Magnetodynamics in Metallic Heterostructures

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****Technical Abstract****This project explores high-frequency magnetodynamics in metallic heterostructures driven by an electric current, both from the fundamental physics point of view as well as from their relevance to the technologically important area of magnetoelectronics, or spintronics. Spintronics is built on a complementary set of phenomena in which magnetic configurations influence transport properties and transport currents alter magnetic configurations. An example of the latter is the so-called spin-transfer-torque phenomenon which refers to a novel method to manipulate spins using an electrical current. This method, based on quantum mechanical exchange interaction, offers unprecedented spatial and temporal control of spin distributions and attracts a great deal of attention because it combines interesting fundamental science with the promise of applications in a broad range of technologies. This project will exploit the recently developed magnetic microcontact spectroscopy technique which is unique in its ability to probe the current-driven magnetodynamics on yet unexplored length and time scales. The advantages of the technique will be used to study spin-transfer-torque in ferromagnets and also to look for novel spin transfer effects in antiferromagnetic materials which have recently been proposed on theoretical grounds. Coherent integration of research and educational activities will expose PhD students to spintronics and prepare them to conduct research and development of economically feasible and innovative applications.****Non-Technical Abstract****Reducing power and increasing speed of logic and memory devices are of perennial interest in electronics. For instance, in magnetic memories, which make use of magnetic moments as the memory bits, it is pivotal to reliably sense (read) and reverse (write) the moments fast and with minimum energy dissipated. Spin-transfer-torque (STT) phenomenon, which refers to a novel method to control and manipulate magnetic moments by an electric current, can provide just that; here the current generates the STT torque on magnetic moments and can be used to write (switch) magnetic bits in storage media as, e.g. in STT Random Access Memory (STTRAM), being touted as a potential "universal" memory incorporating many of the attractive attributes of other memories like flash, SRAM and DRAM. Specifically, the packing density and speed of such a memory should be improved. In this context, the proposed experiments will be a test bed for the speed and scalability limits of such technology. This project will explore high-frequency magnetodynamics driven by an electric current both from the fundamental science point of view as well as from their relevance to applications in high-speed high-density magnetic recording technology. Coherent integration of research and educational activities will prepare PhD students to conduct research and development of economically feasible and innovative applications.