| Recently there have been a number of experiments investigating magnetic nanodot behavior. The research described in this thesis goes a step further and attempts to determine the magnetic alignment of nickel nanodots using a magnetic field produced by an aluminum micro scale wire. This architecture could be potentially used as a memory device in the future. This architecture could offer low power dissipation, high integration density, and room temperature operation, unlike quantum cellular automata (QCA).;The characteristics of the proposed devices could be attractive with modest speed and simple fabrication technology compared to fabrication of current CMOS technology. Aluminum microscale wires and nickel dots across the wire were fabricated. The wires were 250 nm thick, 10 mum wide and 40 mum long. The nickel dots of varying diameter were fabricated using electron beam lithography. The dot diameters range from 200 nm to 500 nm and were 100 nm in thickness. The nanoscale dimension for the dot results in a single domain magnet, which had two preferential directions along the cylindrical axis. The nickel nanomagnet's field was oriented in one specific direction after passing electric current through the aluminum wire. On reversing the current, the nanomagnet's field was oriented in the opposite direction. These directions can be treated as a logic '1' or logic '0'. The orientation of the magnetic dots remained, even after switching off the current. This indicates a memory device. If this prototype is repeated with closely coupled nanodots, computational logic gates can also be formed.;A magnetic field was applied externally across the ferromagnetic dots through an aluminum wire. Switching of the magnetic field in nanodots on application of electric current was observed using a magnetic force microscope (MFM). MFM cantilever phase and amplitude images helped in identifying the reversal of the magnetic polarity of dots. The phase and amplitude images showed dark and bright contrast. Demonstrating a change of these contrasts upon reversing the current in the aluminum wire completed the prototype testing. |
