热效应对电流驱动磁开关的影响  

Influence of Thermal Effect on Magnetic Switching Driven by Current

作　　者：董浩[1,2,3] 陈培毅[1,2,3] 张磊[1,2,3] 任敏[1,2,3] 邓宁[1,2,3] 

机构地区：[1]清华大学微电子学研究所,北京100084 [2]清华大学清华信息科学与技术国家实验室(筹),北京100084 [3]清华大学微纳电子系,北京100084

出　　处：《微纳电子技术》2009年第3期129-133,共5页Micronanoelectronic Technology

基　　金：高等学校博士学科点专项科研基金资助项目(20060003067);973重大科学研究计划资助项目(2006CB921106);自然科学基金资助项目(60606021)

摘　　要：回顾了热助磁开关理论的发展,包括了Neel-Brown弛豫时间理论和Z.Li小组的有效温度或势垒降低模型,前者很好地解释了磁场驱动磁化矢量翻转的热开关过程,但是不能解释电流驱动磁开关工作机理;后者弥补了Neel-Brown理论的不足,较好地说明了电流驱动的磁开关机制,与实验基本符合。有效温度模型解释了开关电流随温度和测量脉冲宽度的下降;按照不同的脉冲宽度划分了开关的热开关和磁动力学开关工作区。在热开关区,临界电流较小,具有低的功耗,但是器件临界电流随温度而变,工作不够稳定且开关速度较慢;在磁动力学开关区,开关速度高,临界电流不随温度变化,工作稳定,但是功耗较大。实际应用中,应考虑适当的折衷。The recent progress of thermally assisted spin torque induced magnetic switching is reviewed, including the Neel-Brown relaxation time theory and Z. Li group＇s effective temperature model. The former explains the thermal switching process well within magnetization reversal driven by the magnetic field, but cannot fit the current induced the magnetic switching. The latter has made up the insufficiency of Neel-Brown theory, which is a good description of the situation with the existence of the spin transfer torque and accords with the experiment. It explains the switching current dropping with the temperature and measuring impulse width. And Two distinct switching modes, thermal activation and magnitic precessional process, are identified. In the thermal activation mode, the small critical current and low power consumption are gotten, but the critical current changes along with the temperature, the work is not stable, moreover the switching speed is slow. In the magnetic precessional process, the switching speed is high, the critical current is independent to temperature, and the work is stable, but the power consumption is larger. The trade-off between the two switching modes should be chosen in the practical application.

关 键 词：热效应 自旋传输矩 Neel-Brown弛豫时间 FOKKER-PLANCK方程 有效温度 尝试时间 

分 类 号：O482.5[理学—固体物理] O488[理学—物理]