Micromagnetic simulation for tunnel junctions with synthetic antiferromagnetic pinned layers annealed at different external fields

被引:16
作者
Liu, YW
Zhang, ZZ
Zhang, ZG
Freitas, PP
Martins, JL
机构
[1] INESC, P-1000 Lisbon, Portugal
[2] Univ Tecn Lisboa, Dept Phys, Inst Super Tecn, P-1096 Lisbon, Portugal
关键词
D O I
10.1063/1.1447484
中图分类号
O59 [应用物理学];
学科分类号
摘要
Bottom-pinned tunnel junctions with synthetic antiferromagnetic (SAF) pinned layers require an annealing step near the blocking temperature under an applied magnetic field to set the exchange direction. Experimental results (anneal at 270 degreesC, for a MnIr/SAF structure) show that the tunnel magnetoresistance signal is strongly reduced (3%) for anneals under an applied field of 2000 Oe, when compared with large tunnel magnetoresistance signals (>20%) obtained for samples annealed either at low (250 Oe) or high (5000 Oe) fields. To clearly understand this behavior, a micromagnetic simulation was performed to demonstrate the magnetization evolution of the SAF layer during the different field anneals. The simulated magnetization configurations indicate that the SAF layer net moment aligns parallel to the applied field (high field anneal) or antiparallel to the applied field (low field anneal), leading in both cases to high TMR signal. After annealing at intermediate field, the SAF net moment rotates almost orthogonal to the annealing field direction, resulting in the measured low TMR signal. (C) 2002 American Institute of Physics.
引用
收藏
页码:8296 / 8298
页数:3
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