1/f noise in linearized low resistance MgO magnetic tunnel junctions
1/f noise in linearized low resistance MgO magnetic tunnel junctions
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DOI：
10.1063/1.2172179
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发表时间：
2006-04-15
影响因子：
3.2
通讯作者：
Maass, W.
中科院分区：
文献类型：
--
作者：
Almeida, J. M.;Ferreira, R.;Maass, W.
在INESC-MN上微加工了在Singulus上制备的低RA MgO磁性隧道结（Ta 3/CuN 30/Ta 5/PtMn 20/CoFe2.5/Ru0.7/CoFeB 3/MgO1.2/CoFeB 3/Ta 5（厚度为纳米））。将结图案化成具有受控形状各向异性（纵横比范围从2到20）的微米尺寸的传感器（5-20 μ m（2））。进一步使用小的外部纵向偏置场（15-30 Oe）来改善传感器线性度。MgO结的电阻面积积为150 Ω μ m（2），最大隧道磁阻为130%。噪声测量是在线性化传感器中完成的，从直流到500 kHz。确定了1/f噪声的磁和磁贡献。由数据拟合得到了近似为2.20 × 10 ~（-9）μ m ~（2）的Hooge参数。对直接实验数据的分析揭示了利用这些MgO结检测10（-10）T/Hz（0.5）量级的磁场变化的可能性，证明了它们用于超低场检测的潜力。(C)2006年，美国物理学会。
Low RA MgO magnetic tunnel junctions prepared at Singulus (Ta 3/CuN 30/Ta 5/PtMn 20/CoFe 2.5/Ru 0.7/CoFeB 3/MgO 1.2/CoFeB 3/Ta 5 (thickness in nanometers) were microfabricated at INESC-MN. The junctions were patterned into micron-sized sensors (5-20 mu m(2)) with controlled shape anisotropy (aspect ratio ranging from 2 to 20). A small external longitudinal bias field (15-30 Oe) was further used to improve sensor linearity. The MgO junctions have a resistance-area product of 150 Omega mu m(2) and a maximum tunnel magnetoresistance of 130%. Noise measurements were done in linearized sensors, from dc to 500 kHz. The magnetic and nonmagnetic contributions to the 1/f noise were determined. From the data fitting, Hooge parameters of similar to 2.20x10(-9) mu m(2) were obtained for the nonmagnetic 1/f noise. Analysis of direct experimental data revealed the possibility to detect variations of magnetic fields in the order of 10(-10) T/Hz(0.5) with these MgO junctions, demonstrating their potential for ultralow-field detection. (C) 2006 American Institute of Physics.