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There are a number of physical systems that may, in principle, be used for computation-and readers may entertain themselves with a number of ingenious ideas, from mechanical devices to slimebased computers [1]. However, for the past 50 years, semiconductor electronic circuitry was the only practical way to do computation. The steady exponential performance growth of integrated electronics, widely known as Moore's law, essentially crushed any ideas for a generalpurpose "exotic" computing device-that is, one that would work using fundamentally different principles [2]. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate that the stray field of a propagating transverse domain wall can switch chains of coupled nanomagnets (nanomagnet wires) to a magnetically ordered, low energy ground state. We fabricated nanomagnet wires consisting of 6 and 20 nanomagnets that were placed adjacent to a domain-wall conductor. Magnetic force microscope images clearly show the nanomagnet wire switching from an initial metastable state to an ordered ground state. This can be exploited for controlled order of nanomagnet switching and for energy-efficient clocking of nanomagnet logic devices. Reference structures were fabricated and characterized to prove our assumptions. [ABSTRACT FROM AUTHOR]

This paper demonstrates the design of nanomagnetic logic (NML) gates with multiple weighted inputs, which are magnetic equivalents of threshold logic gates (TLGs). We use micromagnetic simulations to show that NML TLGs can be constructed with minimum overhead compared to standard NML gates, and they significantly reduce device footprint and interconnection complexity of magnetic logic circuits. As an example, we design a full adder circuit using said TLGs and compare its performance to majority-gate-based NML. [ABSTRACT FROM PUBLISHER]

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]

We present the design and simulation of systolic information processing hardware that is comprised of single domain, Co/Pt magnets (i.e., out-of-plane nanomagnet logic or oNML). The designed circuit can identify instances of a preprogrammed bit sequence in streaming data. The systolic architecture 1) exploits unique benefits of the oNML device architecture such as nonvolatility and inherently pipelined logic with no memory overhead for holding the bits in the pipeline and 2) mitigates less desirable features of oNML such as nearest neighbor dataflow and longer device switching times when compared to a CMOS transistor. The designed layout is verified and analyzed by micromagnetic simulations. We quantify how the performance and energy of oNML information processing hardware compares to CMOS equivalents and conclude that the initial oNML design (including the overhead of magnetic field generation) is about an order of magnitude more power efficient at essentially iso-performance. [ABSTRACT FROM PUBLISHER]

Nanomagnet logic (NML) has received increasing attention as an alternative information processing technology given the potential for low energy dissipation, a relatively advanced experimental state of the art, and intangibles such as inherent radiation hardness and nonvolatility. In order to facilitate the integration of NML-based circuits with transistor-based circuits, a magnetic–electrical interface (MEI) is needed. This paper focuses on the output portion of MEI design, i.e., converting signals from the magnetic domain to the electrical domain. The basic idea of an MEI output is to employ fringing fields from an NML device to set the magnetization state of the free layer of a magnetic tunnel junction. A detailed study of four different MEI output designs is presented which considers metrics such as the clock energy required to set the output state, the magnetoresistance ratio, etc. Simulation-based analysis reveals the pros and cons of each design. A design where multiple NML devices (i.e., free layers) share a large synthetic antiferromagnet is most promising based on our simulation-based, quantitative analysis. [ABSTRACT FROM PUBLISHER]

Nonvolatile data storage in today's computers is based on magnetic materials. Hard disk drives (HDD) feature ferromagnetic thin films for recording bits as regions with different magnetizations in the film. At present, the efforts of decreasing HDD size while increasing storage capacity, however, face fundamental limits, namely, the so-called superparamagnetic effect. Research into new generations of magnetic data-storage devices, amongst others, considers as its basic working principle current-induced magnetic domain-wall motion (CIDWM) in magnetic nanowires. In this paper, we present simulation studies of external magnetic field-induced magnetization reversal and domain-wall motion in nanowires of various sizes and shapes. Our results contribute to the basic design principles applied to magnetic structures used in CIDWM experiments. Parameters, such as wire thickness and wire-pad geometries are investigated, and important threshold magnetic field values are presented. In addition, we introduce a novel method of domain-wall trapping in a magnetic wire using the fringe fields of close-by magnets. [ABSTRACT FROM PUBLISHER]