NANO: Applications, Architectures, and Circuit Design for Nano-scale Magnetic Logic Devices

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

Magnetic systems are attractive for computational logic because they are nonvolatile and offer the promise of low power dissipation per logic operation. Recent work shows that nanomagnets can (1) be configured to realize a universal logic gate (which can be used to implement any Boolean function) and (2) do not possess the disadvantages of the early, bulky, ferrite core magnets. This work will investigate lithographically defined nanomagnets within the quantum-dot cellular automata (QCA) architecture scheme - where the direct physical interaction between individual nanomagnets yields logic functionality. The work proposed here aims to make the jump from studying logic gates to studying simple circuits. Analyzing circuits should in turn provide significant insight as to the expected performance of simple computational systems made from magnetic QCA (mQCA) devices. Systems are the desired end result. The proposal has three main goals: 1. To investigate potential application spaces for systems of mQCA devices. 2. To fabricate the core logic needed for two seemingly well-suited application spaces. 3. To use the designs, insights, and experimental data produced by (1) and (2) to determine whether or not mQCA devices can outperform semiconductor-based equivalents at the systems-level. The performance of nano-scale magnets appears to be competitive with (and is often better than) end-of-the-roadmap CMOS in the context of device density, power consumption, power density, tolerance to thermal fluctuations, and global bandwidth. As the basic components of this technology have been experimentally demonstrated, some of the challenges in determining the viability of this technology now shift to computer scientists. However, this work will also discuss experiments that will involve the fabrication of the "core" parts of the systems to be explored. In the context of systems, magnetic materials could offer simplicity of fabrication, robustness, and true room temperature operation. This might suggest application spaces for mQCA that require robust performance and low power consumption. Magnetic materials are also insensitive to radiation, which might suggest superior performance in harsh operating environments such as outerspace, or for satellite and military applications. At the systems level, this work will target digital signal processing and reprogrammable logic. Experimentally, this work will investigate an I/O structure, efficient interconnect, and a programmable majority gate. Finally, not only will this study provide significant insight as to the viability of magnetic QCA, but much of the proposed work is also implementation independent - and will apply particularly well to systems of molecular QCA devices too.