Low-frequency and shot noises in CoFeB/MgO/CoFeB magnetic tunneling junctions

被引：22
作者：
Arakawa, Tomonori [1 ]
Tanaka, Takahiro [1 ]
Chida, Kensaku [1 ]
Matsuo, Sadashige [1 ]
Nishihara, Yoshitaka [1 ]
Chiba, Daichi [1 ]
Kobayashi, Kensuke [1 ]
Ono, Teruo [1 ]
Fukushima, Akio
Yuasa, Shinji
机构：
[1] Kyoto Univ, Inst Chem Res, Uji, Kyoto 6110011, Japan
来源：
PHYSICAL REVIEW B | 2012年 / 86卷 / 22期
关键词：
ROOM-TEMPERATURE; MAGNETORESISTANCE;
D O I：
10.1103/PhysRevB.86.224423
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
The low-frequency and shot noises in spin-valve CoFeB/MgO/CoFeB magnetic tunneling junctions were studied at low temperature. The measured 1/f noise around the magnetic hysteresis loops of the free layer indicates that the main origin of the 1/f noise is the magnetic fluctuation, which is discussed in terms of a fluctuation-dissipation relation. Random telegraph noise (RTN) is observed to be symmetrically enhanced in the hysteresis loop with regard to the two magnetic configurations. We found that this enhancement is caused by the fluctuation between two magnetic states in the free layer. Although the 1/f noise is almost independent of the magnetic configuration, the RTN is enhanced in the antiparallel configuration. These findings indicate the presence of spin-dependent activation of RTN. Shot noise reveals the spin-dependent coherent tunneling process via a crystalline MgO barrier. DOI: 10.1103/PhysRevB.86.224423
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页数：9
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