CPP-GMR Performance of Electrochemically Synthesized Co/Cu Multilayered Nanowire Arrays with Extremely Large Aspect Ratio
CPP-GMR Performance of Electrochemically Synthesized Co/Cu Multilayered Nanowire Arrays with Extremely Large Aspect Ratio
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DOI：
10.3390/nano10010005
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发表时间：
2020-01-01
期刊：
影响因子：
5.3
通讯作者：
Ohgai, Takeshi
中科院分区：
文献类型：
--
作者：
Kamimura, Himeyo;Hayashida, Masamitsu;Ohgai, Takeshi
阳极氧化铝（AAO）薄膜，其中有许多纳米通道ca。直径75 nm，D和ca. 70 μ m长，L（ca. 933的长径比，L/D）被用作生长Co/Cu多层纳米线阵列的模板材料。采用电化学脉冲电位沉积技术制备了Cu层和Co层交替排列的多层纳米线。Cu层的厚度从约100 μ m调整到约100 μ m。2 ~ 4 nm，Co层的厚度从约100 nm调整到约200 nm。通过控制脉冲电位参数，可以在13 ~ 51 nm范围内实现脉冲电位的测量。为了获得与电沉积的Au薄层电化学原位接触的Co/Cu多层纳米线，脉冲电位沉积持续到约100 V。5000个循环，直到纳米线伸出到AAO模板的表面。电流垂直面巨磁电阻效应（CPP-GMR）达到约1000。23.5%，在室温下的Co/Cu多层纳米线与ca. 3500 Co/Cu双层膜（Cu：1.4 nm和Co：18.8 nm）。随着Co层厚度的减小，由于长自旋扩散极限下的Valet-Fert模型，CPP-GMR值增大。
Anodized aluminum oxide (AAO) films, which have numerous nanochannels ca. 75 nm in diameter, D and ca. 70 mu m in length, L (ca. 933 in aspect ratio, L/D), were used as a template material for growing Co/Cu multilayered nanowire arrays. The multilayered nanowires with alternating Cu layer and Co layers were synthesized by using an electrochemical pulsed-potential deposition technique. The thickness of the Cu layer was adjusted from ca. 2 to 4 nm while that of the Co layer was regulated from ca. 13 to 51 nm by controlling the pulsed potential parameters. To get a Co/Cu multilayered nanowire in an electrochemical in-situ contact with a sputter-deposited Au thin layer, the pulsed potential deposition was continued up to ca. 5000 cycles until the nanowire reached out toward the surface of AAO template. Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) effect reached up to ca. 23.5% at room temperature in Co/Cu multilayered nanowires with ca. 3500 Co/Cu bilayers (Cu: 1.4 nm and Co: 18.8 nm). When decreasing the thickness of Co layer, the CPP-GMR value increased due to the Valet-Fert model in the long spin diffusion limit.