Synthesis and film formation of iron-cobalt nanofibers encapsulated in graphite shell: magnetic, electric and optical properties study
Synthesis and film formation of iron-cobalt nanofibers encapsulated in graphite shell: magnetic, electric and optical properties study
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DOI：
10.1039/c1jm00052g
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发表时间：
2011-01-01
影响因子：
--
通讯作者：
Kim, Hak Yong
中科院分区：
文献类型：
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作者：
Barakat, Nasser A. M.;Abadir, M. F.;Kim, Hak Yong
当这些化合物以封装在石墨壳中的纳米纤维的形式合成时，已经获得了FexCoy合金的新特性。所制备的纳米纤维显示出良好的半导体功能，作为一个薄膜从所制备的纳米纤维支撑在石墨盘上，并可用作二极管具有良好的整流行为。磁性能研究表明，引入的纳米纤维是磁清洁的，因为检测到非常低的反射磁化强度;此外，饱和磁化强度是一个温度无关的属性。光学性质的研究表明，这些纳米纤维的带隙能量为4.73和5.43 eV。通过在750 ℃的氩气气氛中煅烧由聚（乙烯醇）、乙酸亚铁和四水合乙酸钴组成的电纺纤维毡，可以以封装在石墨壳中的纳米纤维的形式生产FexCoy纳米合金。纳米纤维的组成可以通过控制原始静电纺丝溶液的浓度来调节;已经制备了两种制剂：FeCo和FeCo2.7。透射电子显微镜表明，所获得的纳米纤维包裹的石墨壳的厚度接近10 nm。当在静电纺丝过程中使用由聚丙烯腈制成的磁盘作为收集器时，可以成功地制备在其表面上具有从引入的纳米纤维的良好附着的薄膜的石墨盘。所介绍的方法是有效的，简单的，并可用于生产不同的金属合金纳米纤维。
Novel characteristics for the FexCoy alloys have been obtained when these compounds were synthesized in the form of nanofibers encapsulated in a graphite shell. The prepared nanofibers reveal good semiconducting features as a thin film from the prepared nanofibers supported on a graphite disk and could be utilized as a diode with good rectifying behaviour. Magnetic properties study showed that the introduced nanofibers are magnetically clean as very low remanent magnetizations were detected; moreover the saturation magnetization is a temperature-independent property. Optical properties study indicated that these nanofibers have band gap energies of 4.73 and 5.43 eV. FexCoy bimetallic alloys could be produced in the form of nanofibers encapsulated in a graphite shell by calcination of electrospun nanofiber mats composed of poly(vinyl alcohol), ferrous acetate and cobalt acetate tetrahydrate in an argon atmosphere at 750 degrees C. The composition of the nanofibers could be adjusted by controlling the concentration of the original electrospun solution; two formulations have been prepared: FeCo and FeCo2.7. Transmission electron microscopy indicated that the thickness of the graphite shell enveloping the obtained nanofibers is similar to 10 nm. A graphite disk possessing on its surface a well attached thin film from the introduced nanofibers could be successfully prepared when a diskette made of poly(acrylonitrile) was used as a collector during the electrospinning process. The introduced methodology is effective, simple and can be exploited to produce different metallic alloys nanofibers.