T型自由层自旋力矩转移磁隧道结结构的设计与模拟计算

发布时间：2018-04-16 05:27

本文选题：自旋力矩转移磁随机存储器 + 磁隧道结　；参考：《华中科技大学》2013年硕士论文

【摘要】：随着信息技术与信息产业的迅速兴起，特别是多媒体计算机网络在全球的延伸和普及，人们需要存储、处理和传递的数据量呈几何级数式急剧增长，，因此带动了信息存储技术的高速发展。磁随机存储器、由于其非易失性存储、超高的读写次数、低功耗、高存储密度和高读写速度，在未来的存储系统领域引起了广泛的兴趣，是最有希望成为下一代信息存储器的候选存储器之一。MRAM的应用目前还处于发展阶段，其性能还有很大的提升空间。本文提出了一种T型自由层的自旋力矩转移磁随机存储器单元结构，并用微磁模拟软件对此结构进行了建模。研究了T型自由层MTJ磁存储单元结构的TMR值与翻转电流密度之间的关系；从单元的TMR值以及翻转电流密度两个方面比较了T型自由层存储单元与常规结构存储单元之间的性能差异，通过模拟T型自由层存储单元磁矩的翻转分析了这种性能差异的原因。通过ANSYS有限元热模拟说明了T型自由层存储单元上自由层的聚热作用，从弱化自由层垂直磁各向异性强度的角度说明了这种聚热作用对提高磁翻转效率的影响。接着本文对T型自由层结构的磁存储单元提出了优化方案：首先应用微磁模拟研究了T型自由层存储单元的翻转电流密度与上自由层横截面积之间的关系，接着利用有限元热分析方法说明了尽可能地提高T型自由层存储单元的性能同时避免存储单元的温度过高而超过其承受极限的方法。本文最后进行了T型自由层存储单元的热辅助电致磁化翻转的模拟研究。
[Abstract]:With the rapid rise of information technology and information industry, especially the extension and popularization of multimedia computer network in the world, people need to store, process and transfer the data volume in a geometric series of rapid growth.Therefore, it drives the rapid development of information storage technology.Magnetic random access memory (MRAM) has attracted wide interest in future memory systems due to its nonvolatile storage, high read / write times, low power consumption, high storage density and high read / write speed.MRAM is one of the most promising candidate memory for next generation information memory. The application of MRAM is still in the developing stage, and its performance still has a lot of room for improvement.In this paper, a T-type free layer structure of spin torque transfer magnetic random access memory (RRAM) is proposed, and the structure is modeled by micromagnetic simulation software.The relationship between the TMR value of T-type free-layer MTJ magnetic memory cell and the turnover current density is studied.The difference of performance between T-type free layer memory cell and conventional structure memory cell is compared from the TMR value of the cell and the current density of the cell.The reason of this difference is analyzed by simulating the magnetic moment flip of T-type free layer memory cell.The thermal accumulation of free layer on T-type free layer storage cell is illustrated by ANSYS finite element thermal simulation, and the effect of this kind of heat accumulation on improving magnetic turnover efficiency is explained from the angle of weakening the vertical magnetic anisotropy of free layer.Then this paper presents an optimized scheme for the magnetic storage cells of the T-type free layer structure. Firstly, the relationship between the turnover current density of the T-type free layer memory cell and the cross section area of the upper free layer is studied by using the micromagnetic simulation.Then the finite element thermal analysis method is used to illustrate the method of improving the performance of T-type free layer storage cell as much as possible and avoiding the excessive temperature of the storage cell and exceeding its bearing limit.At the end of this paper, the thermo-assisted electromagnetization flip of T-type free layer memory cell is simulated.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333

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