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Dependency of errors in nanomagnet logic datalines on the dipole coupling strength is investigated. Evolution of different types of errors at different coupling strengths is studied. Dipole coupling strength in datalines is varied by changing the inter-magnet spacing from 30nm to 10 nm and the aspect ratios of the 20-nm-thick Supermalloy (Ni79Fe16Mo5) dots from 90×60 nm² to 120×60nm². An error rate improvement up to 46% is observed for inter-magnet space reduction from 30 nm to 10nm. Error rates in datalines with larger spacing are dominated by premature switching, whereas a new type of error, due to the stronger influence of the driver magnets, dominates in datalines with tighter (sub-20-nm) spacing. For same spacing, datalines with lower aspect ratio magnets show higher error rates compared to those with higher aspect ratio. [ABSTRACT FROM AUTHOR]

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]

The static leaf sequencing (SLS) problem arises in radiation therapy for cancer treatments, aiming to accomplish the delivery of a radiation prescription to a target tumor in the minimum amount of delivery time. Geometrically, the SLS problem can be formulated as a 3-D partition problem for which the 2-D problem of partitioning a polygonal domain (possibly with holes) into a minimum set of monotone polygons is a special case. In this paper, we present new geometric algorithms for a basic case of the 3-D SLS problem (which is also of clinical value) and for the general 3-D SLS problem. Our basic 3-D SLS algorithm, based on new geometric observations, produces guaranteed optimal quality solutions using O(1) Steiner points in polynomial time; the previously best known basic 3-D SLS algorithm gives optimal outputs only for the case without considering any Steiner points, and its time bound involves a multiplicative factor of a factorial function of the input. Our general 3-D SLS algorithm is based on our basic 3-D SLS algorithm and a polynomial time algorithm for partitioning a polygonal domain (possibly with holes) into a minimum set of x-monotone polygons, and has a fast running time. Experiments of our SLS algorithms and software in clinical settings have shown substantial improvements over the current most popular commercial treatment planning system and the most well-known SLS algorithm in medical literature. The radiotherapy plans produced by our software not only take significantly shorter delivery times, but also have a much better treatment quality. This proves the feasibility of our software and has led to its clinical applications at the Department of Radiation Oncology at the University of Maryland Medical Center. Some of our techniques and geometric procedures (e.g., for partitioning a polygonal domain into a minimum set of x-monotone polygons) are interesting in their own right. [ABSTRACT FROM AUTHOR]