Spin Torque Oscillators

Fall 2010

Charles Delascasas
Jimmy Zhu
Project description

The purpose of this research is to study and model the response of spin-transfer driven 'spin torque oscillators', a novel device in the emerging field of spintronics. Current composed of spin polarized electrons exerts a pseudo-torque on the magnetic moment of ferromagnetic elements when they flow across it. This quantum mechanical interaction can exceed the current induced magnetic field in the limit of a large current and small magnetic element, allowing the spin-transfer driven effects to be taken advantage of in previously unthought-of ways. The spin torque oscillator uses this spin-transfer to overcome the damping term described in the Landau-Lifshitz-Gilbert equation, enabling the magnetic moment to reach a stable precession. This precession has sparked great interest due to their applications in generating microwaves. This research aims to study the magnetization dynamics of the moments in various multilayer device configurations using MATLAB simulations, and to improve upon the designs of current spin torque oscillators. This will be supplemented by actual measurements of R-H and I-R curves of fabricated STOs in the lab. Frequency response will also be studied.

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