Tuesday, December 8, 2009

Magnetic Cellular Automata



We are interested in Low Energy Computing where computing occurs due to the coupling of the computing elements. In conventional computing, electrons flow from one points to another to process information. In Nano-computing-Resaerch-Group@EE-Univ. of South florida, we pursue a novel cellular automata computing paradigm, where state of the computing elements change and the next computing element couples to the change in the previous computing element and extreme low power dissipation is possible.

We are currently exploring computing with nano-scale soft magnets that are easy to switch, requires no power in the memory state, and can be operated at room temperature. Each magnetic cell is a single domain nano magnet in which all the spins are aligned to one direction. By shape engineering, we can have two dominant state "0" and "1" as shown here. Information processing occurs due to neighbor interactions and there is no physical movement of magnets. In this sense, requirement from Magnetic Cellular automata (MCA) is orthogonal to Magnetic RAM when inter-cell interaction are prohibited. We are however interested in interfacing such systems with MRAM, and sensors providing low energy embedded computing.

In this work, we fabricate nano magnetic structure by E-beam Lithography and observe them qualitatively using Scanning Probe Mucroscope in magnetic mode. So far, varous length of magnetic interconnects, and magnetic crosswires are fabricated.

We have also proposed a spatially moving clocking field for the ordering of the magnets. We are also interested in defect characterization, shape engineering, scaling limits on such devices.

Our recent interest is in creating multi-layer magnetic cells as MQCA elements. We are exploring various clocking and device designs and architectures that can resolve some of the criticism of device integration and low power operation of its previous generation.
We will post a Verilog A model for the cell and architecture shortly once the copyright issues are resolved.