Study Of Spin-Wave Logic Devices

The power consumption of traditional logic devices based on silicon becomes more severe with the decreasing of the size of logic devices, it can’t meet the development requirements of small size and low power consumption of integrated circuit. Logic devices based on new principle are urgent to be studied and developed. Spin-wave based logic devices is the new principle logic devices with a great development potential which was pointed out in 2011 and 2013 version of The International Technology Roadmap for Semiconductor. Spin wave logic devices use the feature of wave to work, it not only has extremely low power consumption and extremely high transmission speed, but also has the possibility to be applied to the quantum computing, implement parallel processing of multiple frequency channel data, greatly improve the ablility of information processing, spin-wave based logic devices can greatly reduce the complexity of the complex logic curcits, help to large-scale intergration of logic devices, therefore the research of spin wave logic devices has become a research hotpot in the industry.Based on the review and analysis of dynamic development of spin- wave logic devices, the paper adopted micromagnetic simulation method to study the realization mechanism of spin wave logic devices.Firstly, this paper studied feasibility of spin-wave majority gate in the nanoscale. The results showed that the structure of logic device with 3- input and 1-output can also evaluate the logic input signals, and thus the majority gate can be fulfilled. Besides, if choose one of the logic input as a control s ignal, logic “And” gate and “O R” gate can be fulfilled. Change the detection point of output spin waves, logic “NAND” gate and “NOT” gate can be fulfilled. So this kind of majority gate has the characteristic of configurable and functional.Secondly, this paper systematically studied the influence of applied spin-polarized current on the phase and amplitude of propagating spin waves in ferromagnetic nanostripe. The results showed that by designing appropriate size and number of pinned magnetic layers, the propagating spin waves can achieve 180°phase shift. Based on the influence of spin-polarized current on the propagating spin waves in ferromagnetic nanostriope, the Mach-Zehnder type interferometer can be used to construct spin-wave based logic “NOT” gate and multi- input logic gate. On this basis, proposed the improved method by applying local spin-polarized current in a single ferromagnetic nanostripe to design spin wave multi- input gate. Construct several STT(Spin- Transfer torque) blocks in a single ferro magnetic nanostripe, and then encode the phase shift of output spin waves in a certain way, so as to fulfill multi- input logic gate. This kind of logic gate structure is more simple compare to the structure of Mach-Zehnder type interferometer, and it supports the expansion of the logic input number.