Dependence on annealing temperatures of tunneling spectra in high-resistance CoFeB/MgO/CoFeB magnetic tunnel junctions

被引：22
作者：
Matsumoto, Rie
Nishiokaa, Shingo
Mizuguchi, Masaki
Shiraishi, Masashi
Maehara, Hiroki
Tsunekawa, Koji
Djayaprawira, David D.
Watanabe, Naoki
Otani, Yuichi
Nagahama, Taro
Fukushima, Akio
Kubota, Hitoshi
Yuasa, Shinji
Suzuki, Yoshishige
机构：
[1] Osaka Univ, Grad Sch Engn Sci, Osaka 5608531, Japan
[2] Canon ANELVA Corp, Elect Device Equipment Div, Tokyo 1838508, Japan
[3] Natl Inst Adv Ind Sci & Technol, Nanoelect Res Inst, Tsukuba, Ibaraki 3058568, Japan
来源：
SOLID STATE COMMUNICATIONS | 2007年 / 143卷 / 11-12期
基金：
日本学术振兴会;
关键词：
magnetic films and multilayers; electronic band structure; electronic transport; tunneling;
D O I：
10.1016/j.ssc.2007.07.001
中图分类号：
O469 [凝聚态物理学];
学科分类号：
070205 ;
摘要：
We investigated the annealing temperature dependence of differential tunneling conductance spectra (dI/dV as a function of V) in CoFeB/teXtUred MgO(001)/CoFeB magnetic tunnel junctions (MTJs) that exhibit the giant tunneling magnetoresistance (TMR) effect at room temperature. The spectra were strongly affected by annealing the MTJs. A reduction in dI/dV at around 300 mV was observed only in annealed MTJs in which the CoFeB electrodes were crystallized in a bcc(001) structure. Because the reduction in conductance was observed in both MTJs that have a 1.8-nm-thick MgO barrier and MTJs that have a 3.2-nm-thick MgO barrier, we concluded that Delta(5) and Delta(2') evanescent states, which rapidly decay in the MgO tunneling barrier, are not the cause of the reduction in conductance. We believe the cause of the reduction is either the electronic structure of the interfaces between MgO(001)/bcc CoFeB(001) after annealing or a particular feature of Delta(1) states in MgO(001) or bee CoFeB(001). () 2007 Published by Elsevier Ltd
引用
收藏
页码：574 / 578
页数：5
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