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Unformatted text preview: Magnetic cellular automata coplanar cross wire systems Javier F. Pulecio a ! and Sanjukta Bhanja b ! Department of Electrical Engineering, Nano Computing Research Group, University of South Florida, Tampa, Florida 33612, USA s Received 29 June 2009; accepted 4 August 2009; published online 4 February 2010 d Quantum cellular automata has proposed an exclusive architecture where two coplanar perpendicular wires have the ability to intersect one another without signal degradation. The physical realization of cross wire architectures has yet to be implemented and researchers share concerns over the reliability of such a system. Here we have designed a coplanar cross wire layout for magnetic cellular automata s MCA d and have fabricated two different systems. The first system was implemented via two ferromagnetic coupled coplanar crossing wires and demonstrated all possible logic combinations. The second more complex cross wire system consisted of nine junctions and one hundred and twenty single domain nanomagnets. The complex systems ability to reach an energy minimum combined with the demonstration of all combinations of the smaller system leads us to conclude that a cross wire system is physically feasible and reliable in MCA. 2010 American Institute of Physics . f doi: 10.1063/1.3213371 g I. INTRODUCTION A theoretically unique characteristic of quantum cellular automata s QCA d is the ability to not only propagate informa- tion along two independent nonintersecting coplanar wires, but also to transmit information via two independent copla- nar perpendicular crossing wires. Figure 1 provides a visual representation of two different technologies implementing crossing wires. If two conventional metal interconnects are fabricated in such a manner as depicted in Fig. 1 s a d , the junction, where the two crossing wires intersect, could cause an electrical short s a logical 1 and 0 given simultaneously on the wires d . Consequently, multiple layers are needed to over- come layout scenarios where wires cross over one another. This increases the complexity of fabrication by creating mul- tiple layer alignment steps, as well as expanding the non- trivial intricacies of designing the layout of a system cur- rently containing over two billion transistors. As technology continues to scale deeper into the lower boundaries of nano- space, the delicacy of multiple layer alignment could prob- ably lower the yield of working devices. Electronic QCA s EQCA d has theoretically proposed a coplanar cross wire system. In EQCA, devices are coupled via columbic field interactions rather than physical connec- tions. Figure 1 s b d demonstrates two orthogonal sets of EQCA wires. In order to limit coupling interference between the two wires, wire 1 is comprised of cells that are oriented in a normal fashion, while in wire 2, the cells are rotated by 45. Due to the physical nature and the need for experimental data of the system, researchers have expressed concerns over...
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This note was uploaded on 11/28/2011 for the course COMP 790 taught by Professor Staff during the Fall '08 term at UNC.
- Fall '08