准一维磁性隧道结中的散粒噪声  

The shot noise in quasi one-dimensional magnetic tunnel junctions

作　　者：吕厚祥 谢征微[2] LV HouXiang;XIE ZhengWei(Department of Medical Technology, Bijie Medical College, Bijie 551700, China;College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610101, China)

机构地区：[1]毕节医学高等专科学校医学技术系,毕节551700 [2]四川师范大学物理与电子工程学院,成都610101

出　　处：《中国科学：物理学、力学、天文学》2018年第5期76-83,共8页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：四川省教育厅自然科学基金重点项目(批准号:13ZA0149);毕节市科学技术局毕节医学高等专科学校科学技术联合基金项目(编号:毕科联合字X[2016]16)资助

摘　　要：基于自由电子近似,研究了铁磁金属/绝缘体/铁磁金属(FM/I/FM)隧道结中的散粒噪声.计算结果表明:不同自旋取向的电子Fano因子随绝缘体厚度的增大而增大;当绝缘体厚度较小时,上、下自旋电子的Fano因子随入射电子能量的增大缓慢减小,当绝缘体厚度较大且电子能量处于低能区时不同自旋方向的电子Fano因子相同,但在高能区上、下自旋电子Fano因子急剧减小且出现共振特性.此外,上、下自旋电子的Fano因子随两端铁磁体中分子场和磁矩夹角的变化表现出明显的分离特性.上、下自旋电子的Fano因子和隧穿电导随绝缘体厚度和入射电子能量的变化位相始终相反.Based on the free electron approximation, the shot noise of spin-polarized electron tunneling ferromagnetic metal/insulator/ferromagnetic metal（FM/I/FM） tunnel junctions is investigated. The calculated results show that the Fano factors for electrons with different spin orientations increase with the insulator thickness. When the thickness of insulator is small, the Fano factors for up and down spin electrons decrease slowly with the increase of incident electron energy.For large insulator thickness, the electrons Fano factors for different spin directions are the same when the incident electron energy is located in the low energy region, but decrease sharply and appear resonance when the incident electron energy is located in the high energy region. In addition, with the changes of the angle of magnetic moment in two ferromagnetic layers, the electrons Fano factors for different spin directions show obvious separation characteristics.When the magnetic moments in two ferromagnetic layers are antiparallel, the Fano factors tend to same. At the same time, with the increase of the thickness of the insulator and the incident electron energy, the phase variations of between the tunneling conductances and the Fano factors are always opposite.

关 键 词：磁性隧道结 散粒噪声 隧穿电导 磁矩 

分 类 号：O471[理学—半导体物理]