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Study on the Electrochemical Preparation and Properties of Co/Cu Multilayered Nanowires

Author: SongZhenXing
Tutor: YaoSuZuo
School: Tianjin University
Course: Applied Chemistry
Keywords: Alumina Template Electrodeposition Co / Cu multilayered nanowires GMR
CLC: TB383.1
Type: Master's thesis
Year: 2007
Downloads: 118
Quote: 0
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Abstract

In this paper, the aluminum anodic oxide film (AAO) as a template prepared by electrochemical nanotubes Co, Co nanoparticles, Co nanowires, Cu nanowires, and Co / Cu multilayer nanowires. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) and the self-assembly of giant magnetoresistance (GMR) test systems for the nanowires were characterized and Performance. Prepared by the secondary porous anodized aluminum anodized aluminum, membrane pore density, highly ordered arrangement. Lift-off technique by the inverse power the oxide film is peeled off from the aluminum substrate and the barrier layer is removed with phosphoric acid, obtained through the nanopore. And used to package into AAO electrode. Porous alumina template, prepared by electrochemical deposition Cu, Co nanowire arrays, Co nanotube arrays, Co nanoparticle arrays. XRD showed Cu nanowires with a face-centered cubic (fcc) crystal structure, Co nanowires and nanotube arrays with hcp (hcp) structure. VSM shows 80nm diameter of Co nanowires direction parallel to the magnetic field and perpendicular to the long axis of the nanowire arrays were coercivity 1010Oe, 380Oe; 120nm in diameter of Co nanowires were 900Oe, 330Oe; diameter of 120nm Co nanotube arrays coercivity were 460Oe, 126Oe. Most Co grain easy axis of magnetization perpendicular to the film surface. Porous alumina template was prepared using electrochemical deposition of Co nanoparticles two diameters arrays. Porous alumina template, the deposition method of direct current slot AAO template prepared using sub-layer thickness was 10nm, 25nm, 100nm, 150nm diameters of 80nm, 120nm of Co / Cu Multilayer Nanowire Arrays, which the thickness of the magnetic layer is consistent with the non-magnetic layer thickness. XRD patterns indicate that the Cu is face-centered cubic crystal structure (fcc) structure, Co crystal form is hexagonal close-packed (hcp) structure. Co has a hcp structure of [002] crystal plane in the growth of the nanowires have a preferred orientation, multilayer nanowires unaltered Cu and Co crystal. VSM show nanowire arrays easy magnetization direction parallel to the nanowires. Equivalent layer thickness of 80nm in diameter nanowires coercivity higher than a diameter of the nanowire array 120nm coercivity, but the excess is smaller in value. Have the same diameter nanowires coercivity increases as the layer thickness decreases. Using self-assembly device testing the Co / Cu multilayered nanowires giant magnetoresistance change rate. Diameter of 80nm multi-line array of giant magnetoresistance change rate with the sub-layer thickness increases first and then decreases, the layer thickness of 25nm multi-layer line array has a maximum rate of change of giant magnetoresistance, when the sub-layer thickness greater than 100 nm giant magnetoresistance change rate is equal to only basic values ??of magnetic metal alloys. The diameter of 120 multi-line array of giant magnetoresistance change rate than the corresponding 80nm multi-line array of small, but the trend is still with the sub-layer thickness increases first and then decreases, the sub-layer thickness is 25nm multi-layer line array has a maximum rate of change of giant magnetoresistance. In this experiment, the test conditions and test environment of Co and Cu spin diffusion length (SDL) between a value of less than 100nm.

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