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In Nanomagnet Logic, an electronic read-out device converts magnetization to electronic signals. A giant magnetoresistance (GMR) stack, with simple deposition procedures, is a good candidate for this purpose. In this paper, the authors propose a way to pattern GMR films with the help of a CO2 snow-jet to simplify device fabrication procedures. A scanning electron microscope and a vibrating sample magnetometer were used to characterize the devices and verify the feasibility of the fabrication method. Results have shown that the CO2 snow-jet process can remove sidewalls of nanopillars that are formed after lift-off of sputtered films, and the nanopillars are uniform in shape and size. This method presents a new way to fabricate electronic readout devices for Nanomagnet Logic circuits. [ABSTRACT FROM AUTHOR]

We report a clock/logic/input structure for nanomagnet logic (NML) that implements a two-input slant-based OR gate with both clocking and input programming through current pulses. The clock line is a copper conductor embedded in a Si substrate with CoFe as a flux concentrator. Inputs are implemented with overlaid and dedicated bias lines. The programmability of such inputs allows us to test the same NML device for all possible input combinations. Results are determined by magnetic force microscopy. This scheme is easy to fabricate and can control thicker (20–30 nm) input nanomagnets. Close proximity of bias lines in such a structure allows us to investigate the effect of overlapping bias fields. We also report micromagnetic simulations that relate the slant in the output magnet to the dimensions of the input nanomagnets required to effect proper logic operation. [ABSTRACT FROM AUTHOR]

We present the experimental realization of a full adder circuit using Nanomagnet Logic (NML). The circuit relies heavily on the properties of asymmetric slant magnets that allow robust operation and reduced footprint. We demonstrate stand-alone NML majority gates and wires, and interconnect these components into an NML full adder that functions properly for all 8 input combinations. To our knowledge, this is the first working implementation of an NML full adder from in-plane magnetized nanomagnets, and one of the very few existing non-electrical, room temperature nanoscale computing units. [ABSTRACT FROM AUTHOR]

We study the switching behavior of variously shaped, near-single-domain nanomagnets for nanomagnet logic (NML) applications. Magnets in the size range of 60\,\times\,100 to 60\,\times\,200 nm, with different lengths and end-shapes are fabricated and characterized, and the results compared to temperature-dependent micromagnetic simulations. In this study, the length of the nanomagnets is more important to the switching properties than is end shape. However, for sharper magnets, temperature fluctuations play a large role in determining the switching field. [ABSTRACT FROM AUTHOR]

In nanomagnet logic (NML), tens-of-mT fields are required to initiate the ordering of nanomagnets, and clock them into their computational ground state. This work investigates material-based approaches that are being used to reduce the nulling clock field. As test cases, arrays of both standalone and coupled magnets are covered with enhanced-permeability dielectric (EPD) films. Experimental results demonstrate that EPDs can reduce the fields required to saturate standalone magnets along the hard-axis by 60%, and coupled magnets by 75%. Experiments show that the remanent magnetization of a nanomagnet array is unchanged after being coated with EPDs, demonstrating that no undesired remanence is added to the NML system. The 75% reduction in switching field translates to a 94% reduction in energy dissipation due to reduced Joule-heating of field-generating wires. [ABSTRACT FROM AUTHOR]

The article presents information on the nanomagnet logic devices that do not require a magnetic field for clocking and requires support circuitry to re-evaluate a circuit when new inputs are available. Topics include torques generated by the spin Hall effect, magnetic field and potential energy reductions associated with spin-Hall-effect clocking. Other topics include complete energy analysis.