Magnetic quantum-dot cellular automata: Recent developments and prospects

Quantum-dot Cellular Automata (QCA) is a computational paradigm that uses local physical coupling between nominally identical bistable building blocks (cells) assembled into arrays to perform binary logic functions. QCA offers low power dissipation and high integration density of functional elements. Depending upon the choice of local fields causing interactions between the cells, different types of QCA are possible, such as magnetic, electronic, or optical. Here we discuss recent developments in the field of magnetic QCA (MQCA) all-magnetic logic where planar, magnetically-coupled, nanometer-scale magnets are assembled into the networks that perform binary computation. The nanomagnets are defined by electron beam lithography. We demonstrate the operation of basic elements of MQCA architecture such as binary wire, three input majority logic gate, and their combination, and discuss interfacing such systems with conventional CMOS-based logic.