Fabrication And Characterization Of Cobalt-Diamond-like-Carbon (Co-DLC) Nanocomposites

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Title: Fabrication And Characterization Of Cobalt-Diamond-like-Carbon (Co-DLC) Nanocomposites
Author: Shebe, Gunjan
Abstract: In recent years , synthesis of magnetic nanocomposites has been receiving significant attention . These nanocomposites offer opportunities to develop active nanomaterials with various applications like magnetic data storage and biomedical applications . They can be designed to provide excellent magnetic properties . However , high saturation magnetization materials , such as Co are not biocompatible . Thus , designing nanocomposites with magnetic phase embedded in biocompatible protective shells is of immense interest . In this study , Co -DLC nanocomposites were synthesized using a hybrid CVD /PVD technique and different combination of processing parameters were used to vary the concentration of Co in the nanocomposites . X -ray photoelectron spectroscopy showed , that with increase in the Co content from 50 at % to 65 at % the sp3 /sp2 ratio decreases from 1 .3 to 0 .87 that consequently decrease hardness from 11 .3 GPa to 9 GPa . An increase in the Co content was observed to increase the coefficient of friction . TEM images for all the nanocomposites from 25 at % to 65 at % showed Co nanocolumns encapsulated by DLC matrix . The nanocolumn exhibited wide variation from 6 nm to 14 nm . As -deposited Co -DLC was found to have ε -Co and DLC matrix . Magnetic measurements for as -deposited films illustrated that , nanocomposites with lower Co content and having small particles size shows superparamagnetic behavior , whereas nanocomposite with higher Co content of 65 at % showed ferromagnetic behavior . On annealing at 250oC and 500oC , all the nanocomposites exhibited ferromagnetic behavior accompanied by increase in the coercivity and saturation magnetization . On annealing at 500oC , nanocomposite with 65 at % Co showed dramatic increase in the saturation magnetization and coercivity . Thus , annealing treatment can be used to tailor the magnetic properties of the nanocomposites and makes it suitable for various applications like sensor and biological .
URI: http : / /hdl .handle .net /10106 /754
Date: 2008-04-22


Fabrication And Characterization Of Cobalt-Diamond-like-Carbon (Co-DLC) Nanocomposites. Available electronically from http : / /hdl .handle .net /10106 /754 .

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