中国物理B ›› 2015, Vol. 24 ›› Issue (7): 78504-078504.doi: 10.1088/1674-1056/24/7/078504
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郭会强a, 唐伟跃a, 刘亮b c, 危健b c, 李大来d, 丰家峰d, 韩秀峰d
Guo Hui-Qiang (郭会强)a, Tang Wei-Yue (唐伟跃)a, Liu Liang (刘亮)b c, Wei Jian (危健)b c, Li Da-Lai (李大来)d, Feng Jia-Feng (丰家峰)d, Han Xiu-Feng (韩秀峰)d
摘要: Low frequency noise has been investigated at room temperature for asymmetric double barrier magnetic tunnel junctions (DBMTJs), where the coupling between the top and middle CoFeB layers is antiferromagnetic with a 0.8-nm thin top MgO barrier of the CoFeB/MgO/CoFe/CoFeB/MgO/CoFeB DBMTJ. At enough large bias, 1/f noise dominates the voltage noise power spectra in the low frequency region, and is conventionally characterized by the Hooge parameter αmag. With increasing external field, the top and bottom ferromagnetic layers are aligned by the field, and then the middle free layer rotates from antiparallel state (antiferromagnetic coupling between top and middle ferromagnetic layers) to parallel state. In this rotation process αmag and magnetoresistance-sensitivity-product show a linear dependence, consistent with the fluctuation dissipation relation. With the magnetic field applied at different angles (θ) to the easy axis of the free layer, the linear dependence persists while the intercept of the linear fit satisfies a cos(θ) dependence, similar to that for the magnetoresistance, suggesting intrinsic relation between magnetic losses and magnetoresistance.
中图分类号: (Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields)