Research On Key Technologies Of Magnonic Logic Devices

The development of traditional“charge-based CMOS devices”is subject to significant obstacles due to the physical limits,which leads the focus of investigation to the development of“non-charge-based devices”.Among these exploring devices,the magnonic functional devices that use the spin waves generated by the collective precession of electronic spins as information carriers are expected to become a strong competitor of novel devices in the post-Moore era.Logic gate is an important functional device for information transmission and processing.Over the past decade,the magnonic phase shifter,which is the key device of magnonic logic gates,has been extensively studied and discussed by the academic community.However,there are several major challenges:?1?Phase-shifting efficiency problem such as long phase-stabilization time and inaccurate phase-shifting results.?2?Control problem.There are few types of current control methods at present,and the extra power consumption is quite huge.?3?Applicability problem.Such as the mismatch of device size,external field environment,signal frequency and CMOS technology.?4?Signal attenuation problem.For those above problems,this thesis proposes a reconfigurable magnonic phase shifter.In terms of functionality,the proposed magnonic phase shifter has reconfigurable structure,dual operating modes,wide application frequency bands,high stability,and low power consumption.In terms of applicability,it has advantages in the miniaturization,no dependence of external magnetic field,and a wide range of compatibility.The main work of this thesis includes:Firstly,designing a magnetic phase shifter model and verifying the model using the micromagnetic simulation software OOMMF.Secondly,performing functional verification simulation according to the two operating modes and analyzing the phase-shifting waveform results.Thirdly,a series of simulations are carried out to explore the affecting factors such as size of the device,frequency and so on.Based on the above analysis of the feasibility and applicability of the device model,the corresponding conclusions are given.Finally,a basic XNOR logic gate was constructed based on the magnonic phase shifter and simulation results supported the correctness of the model.Through the investigation in this thesis,the following conclusions were obtained.?1?The proposed magnonic phase shifter possesses two operating modes,the static mode and the dynamic mode.In the static mode,the switching between phase-shifting state and normal state is achieved by a current pulse of approximately 45 mA for 250 ps.In the dynamic mode,it could ultilize as a real-time controllable magnonic phase shiter or a spin valve.For phase shifters,it is in the normal state when the input current is about 2.8 mA,while it is in the phase-shifting state when there is no input current.For spin valves,it is closed when the input current is about 0.8 mA,and it is open when there is no input current.?2?The proposed magnonic phase shifter possesses a wide range of applicability.Through a series of simulation investigations,it is found that the ratio of the width of waveguide to the length of the resonator should be kept at an appropriate value?about1/3?to ensure the phase-shifting effect.Under the appropriate ratio,the waveguide width can have a selection floating range of 10%,while the size of the resonator is extremely sensitive and is closely related to the application frequency.The empirical formula obtained according to the simulation results shows that there is a linear relationship between the length of the resonator l and the application frequency f_?,f_?=k*l+C,where k=0.04 GHz nm^-1 and C=4.5 GHz.?3?The feasibility analysis of the proposed device model shows that the variation of the spacing distance?2 nm⁴ nm?or the material damping coefficient?0.002⁰.01?will not significantly affect the phase-shifting effect.Additionally,using the material with low damping factor can offset the attenuation of spin waves.?4?The proposed phase shifter is characterized by wide application frequency band?in this model is 8.5 GHz¹1.0 GHz?,small occupied area?in this model is about 150×50 nm²?,extremely low power consumption,no dependence of external magnetic field,and wide application scenarios.?5?A XNOR logic gate based on the proposed mangonic phase shifter is designed,and the expected waveform results are obtained under various input simulation conditions.The simulation results support the correctness of the proposed magnonic phase shifter model and its applicability.