Design of a spin-wave majority gate employing mode selection

Abstract

The design of a microstructured, fully functional spin-wave majority gate is presented and studied using micromagnetic simulations. This all-magnon logic gate consists of three-input waveguides, a spin-wave combiner and an output waveguide. In order to ensure the functionality of the device, the output waveguide is designed to perform spin-wave mode selection. We demonstrate that the gate evaluates the majority of the input signals coded into the spin-wave phase. Moreover, the all-magnon data processing device is used to perform logic AND-, OR-, NAND-and NOR-operations.In spintronics the degree of freedom of the spin is used to transmit information. Spin and, thus, angular momentum cannot only be transmitted by electrons, but also by magnons, the quanta of the dynamic excitations of the magnetic system -spin waves. It is possible to encode information in the phase or amplitude of such spin waves and to have it transmitted through spin-wave waveguides. Moreover, the wave properties allow for efficient data processing through the exploitation of the interference between spin waves.[1-8] An important step towards the application of spin-wave devices in modern information technology is the realization of spin-wave logic gates. In this context, the majority gate is of special interest since it allows for the evaluation of the majority of an odd number of input signals, as given in Tab. I. Furthermore, not only can majority operations be performed with this gate but also AND-or OR-operations, if one input (see input 3 in Tab. I) is used as a control input. Hence, the advantage of the majority gate is its configurability and functionality.[9] In a spin-wave majority gate the phase φ of the waves is used as an information carrier (φ 0 corresponds to logic "0", logic "1" is represented by φ 0 + π). Although the idea of such majority gates was presented earlier, [9,10] no practical realization suitable for the integration into magnonic circuits has thus far been proposed.One of the main problems of a realistic spin-wave majority gate is the coexistence of different spin-wave modes with different wavelengths at a fixed frequency in the structure.[11] As a result, the output signal is given by overlaying waves of various phases and, thus, the majority function is lost. As a solution, a design which guarantees for a single-mode operation has to be used. Here, we present the design of an all-magnon majority gate and prove its functionality using numerical simulations. The width of the output waveguide has been chosen in a way such as to obtain single-mode operation. The operational characteristics of the majority gate have been studied for different phases. AND-, OR-, NAND-and NOR-operations have been demonstrated using the same * Electronic address: klingles@rhrk.uni-kl.de majority gate device.For the simulations, the material parameters of 100 nm-thick Yttrium-Iron-Garnet (

Measurements of the exchange stiffness of YIG films using broadband ferromagnetic resonance techniques

“…New technologies employing YIG are being developed and new physical phenomena were investigated. Logic operations with spin waves in YIG waveguides [2,3,4], data-buffering elements [5] and magnon transistors [6] are only a few examples for the latest technology progress. Especially, YIG films of nanometer thickness [7,8,9,10,11,12] are of large importance since they allow for the realization of nano-and microstructures [6,8,13,14] and an enhancement of spin-transfer-torque related effects [12,15].…”

Spin wave eigenmodes in transversely magnetized thin film ferromagnetic wires

“…More recently, ferromagnetic nanowires proved to be useful for studies of inverse spin Hall effect 19 and spin orbit torques [20][21][22][23] . Furthermore, several realizations of spintronic logic gates [27][28][29][30][31][32] and spin wave guides 33 based on ferromagnetic nanowires have been recently proposed. Detailed understanding of magneto-transport and magneto-dynamic effects in ferromagnetic nanowires rely on the quantitative description of spin waves in this important confined geometry.…”

Optically reconfigurable magnetic materials

“…Periodic variation of the magnetic material's parameters allows the realization of magnonic crystals with novel properties not found in the unstructured material. For example, the dispersion relation of spin waves can be controlled to achieve new schemes for spin-wave-based computing [1][2][3][4][5][14][15][16][17] . The spin-wave dispersion relation depends on many parameters, such as the geometry of the spin-wave waveguide (film thickness and waveguide width), external magnetic field H ext , and saturation magnetization M S .…”