Research On The Properties Of Antidot Array Films And The Current Driven Domain Wall Motion And Tunnel Junction Reverse

The era of information and social networking has generated and stored large amounts of information due to the emergence of high-performance computers and mobile digital devices,and traditional storage technologies have become increasingly difficult to meet the growing desire for high-performance storage.Existing storage devices such as Static Random-Access Memory(SRAM),Dynamic Random-Access Memory(DRAM),and Flash Memory(Flash)all use electronic charge to store information.The presence or absence of charge in each memory cell respectively represents "0" and "1" in the computer binary code.Once the power is turned off,the data in SRAM and DRAM will disappear,which cannot be used for long-term data storage.In addition,the integration density of SRAM is low and the cost is high.However,although the flash memory can realize the existence of data after power-off,the reading and writing speed is slow,and the storage particles are prone to excessive wear and reduce the service life.Therefore,the storage technology field urgently needs to develop a new generation of storage technology to meet the needs of high density,low energy consumption and high reading and writing speed.In the past two decades,the tunnel magnetoresistance effect(TMR)and the spin transfer torque effect(STT)found in the field of spintronics have made it possible to develop a new generation of storage technology using the spin properties of electrons.The above effect can effectively control the magnetization reversal of the ferromagnetic film by using only the current,thereby providing an efficient and energy-saving reading and writing scheme for the magnetic memory.At the same time,the rapid development of nano-manufacturing technology has made it possible to modulate the magnetic properties of materials from microstructures,providing conditions for the development of ultra-high-density memories.Compared with experimental methods,micromagnetic simulation technology allows people to conduct exploratory research on nanomagnetic problems under experimentally constraints,thus providing predictive theoretical guidance for experiments.As one of the important tools for designing and developing magnetic material devices,micromagnetics has been widely used in the development of magnetic recording media,hard disk read heads,magnetic random access memories and magnetic sensors.Based on the above research background,this paper uses micromagnetic simulation to study the dynamic process of anti-dot array film,current-driven magnetic domain wall movement and magnetic tunnel junction inversion from the perspective of system energy change and magnetization flip mechanism,,which provides theoretical guidance for its practical application.The research contents of this paper are mainly divided into the following parts:1.The research contents of this paper are mainly divided into the following parts:The mechanism of magnetic domain and magnetic domain wall formation is introduced.Based on this,the influence of anti-point array on the magnetic reversal mechanism and performance of magnetic thin film is studied.The results show that the antidot arrays can significantly increase the coercive force of the film,in which the smaller nanopore mainly acts as a magnetization nucleation point in the process of magnetization reversal,while the larger nanopore mainly acts as a pinning point to hinder the movement of the magnetic domain wall.It is proved that the performance of magnetic nano-films can be effectively modulated by introducing antidot arrays with different apertures and arrangements.2.The types of magnetic domain walls and their existence conditions are introduced.The effects of current density and nanowire cross-section on the magnetic domain wall movement are studied.The scheme of introducing periodic notches and local heating zones in nanowires to suppress Walker collapse is proposed.The results show that the current density and crosssectional aspect ratio increase within a certain range can significantly increase the moving speed of the magnetic domain wall.By properly setting the periodic notch and the local heating zone,the Walker collapse can be effectively suppressed,so that the magnetic domain wall can stably move at a high speed,and the energy displacement is reasonably explained.3.The effects of temperature field and structural defects on the magnetization reversal mechanism and switching time of an in-plane anisotropic magnetic tunnel junction(MTJ)are studied,and a soft magnetic embedded composite free layer is proposed to reduce the critical current and the reversal time of perpendicular anisotropic tunnel junction(pMTJ).The results show that the temperature field can significantly reduce the "latency period" before the magnetic moment precession,and the reasonable structural design can change the shape anisotropy of the free layer,thus achieving the rapid reversal of the MTJ.The embedding of the soft magnetic region changes the magnetization reversal mechanism of the pMTJ,thereby reducing its critical current and reversal time.