【作者】 刘春明； 葛世慧； 姜丽仙； 寇晓明； 李斌生； 池俊红； 王新伟； 李成贤；

【Author】 Chunming Liu, Shihui Ge, Lixian Jiang, Xiaoming Kou, Binsheng Li, Junhong Chi, Xinwei Wang and Chengxian Li Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000

【机构】 兰州大学磁学与磁性材料教育部重点实验室；

【摘要】 用射频磁控溅射技术制备了[SiO₂（t₁）/Fe₂₅Ni₇₅（t₂）]_N多层膜系列(其中t₁和t₂分别代表SiO₂层和Fe₂₅Ni₇₅层的厚度,N代表层数)。研究发现,对[SiO₂（3.3 nm）/Fe₂₅Ni₇₅（t₂）]₁₀系统,当Fe₂₅Ni₇₅层厚度小于2.4 nm时,Fe₂₅Ni₇₅层从连续变为不连续;在t₂=2.1 nm时,隧道磁电阻（TMR）有极大值,为-0.64%,当温度高于180K时,InR正比于T^-1/2,表明导电机制为热激发的隧穿导电;对[SiO₂（1.8 nm）/Fe₂₅Ni₇₅（1.6 nm）]_N系统,发现磁电阻和电导率先随着层数的增加而增加,然后趋于饱和。更多还原

【Abstract】 A Series of [SiO₂ （t₁）/Fe₂₅Ni₇₅（t₂）]_N multilayer films are fabricated using radio frequency magnetron sputtering technique, in which t₁, t₂ and N represent the thickness of SiO₂ layer, the thickness of Fe₂₅Ni₇₅ layer and the bilayer number, respectively. For [SiO₂ （3.3 nm）/Fe₂₅Ni₇₅ （t₂）]₁₀ system, it is found that Fe₂₅Ni₇₅ layer changes from continuous to discontinuous at its thickness smaller than 2.4 nm, when t₂=2.1 nm, the tunneling magnetoresistance （TMR） has a maximum value of -0.64%, and the logarithmic resistance ln（R） is nearly proportional to T^-1/2at T>180 K, which indicates a thermal excitation tunneling mechanism; For [SiO₂ （1.8 nm）/Fe₂₅Ni₇₅（1.6 nm）]_N system, with the increasing of N, TMR and conductivity are enhanced firstly and then goes to saturation.更多还原