Article

Structural and magnetic properties of Zn1-xcoxO nanorods prepared by microwave irradiation technique.

School of Nano and Advanced Materials Engineering, Changwon National University, Changwon, Gyeongnam, 641-773, Korea.
Journal of Nanoscience and Nanotechnology (Impact Factor: 1.34). 02/2012; 12(2):1386-9. DOI: 10.1166/jnn.2012.4631
Source: PubMed

ABSTRACT We have successfully synthesized large-scale aggregative flowerlike Zn1-xCo(x)O (0.0 < or = x < or = 0.07) nanostructures, consisting of many branches of nanorods at different orientations with diameter within 100-150 nm (tip diameter approximately 50 nm) and length of approximately 1 microm. The rods were prepared using Zinc nitrate, cobalt nitrate and KOH in 180 Watt microwave radiation for short time interval. The synthesized nanorods were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM) and DC magnetization measurements. XRD and TEM results indicate that the novel flowerlike nanostructures are hexagonal with wurtzite structure and Co ions were successfully incorporated into the lattice position of Zn ions in ZnO matrix. The selected area electron diffraction (SAED) pattern reveals that the nanorods are single crystal in nature and preferentially grow along [0 0 1] direction. Magnetic studies show that Zn1-xCo(x)O nanorods exhibit room temperature ferromagnetism. This novel nanostructure could be a promising candidate for a variety of future spintronic applications.

0 Bookmarks
 · 
157 Views
  • Current Applied Physics 07/2013; · 2.03 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Herein, pure and 3 % transition metals (TM; Cr2+ and Fe2+ ions)-doped ZnO nanostructures with high aspect ratios were prepared by microwave–hydrothermal method. X-ray diffraction, selected area electron diffraction and high resolution transmission electron microscopy analyses revealed that all the TM (Cr2+ and Fe2+ ions)-doped ZnO nanostructures have wurtzite structure and no secondary phase was detected. Field emission scanning electron microscopy and transmission electron microscopy results confirmed a higher aspect ratio and highly crystalline nature of nanostructures. Raman spectra reveled that no defect related mode was observed which indicated that the nanostructures have high quality and negligible defects. The value of bandgap was found to be close to the standard value of ZnO, and increased with the increase in atomic number of TM dopants, which indicated that the Cr2+ and Fe2+ ions were uniformly substituted in ZnO. Room temperature ferromagnetism was observed in all the TM (Cr2+ and Fe2+ ions)-doped ZnO nanostructures and the value of saturation magnetization (Ms) and remanent magnetization (Mr) were increased with TM (Cr2+ and Fe2+ ions) dopants. The modification in the magnetization and Hc by microwave hydrothermal might be due to the high aspect ratio of nanostructures. Hence, these nanostructures pave the way for development of multifunctional spintronics and optoelectronic devices that integrate structural, morphological, optical, and magnetic properties.
    Journal of Sol-Gel Science and Technology 10/2014; 72(1). · 1.55 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Herein, the effect of different TM (Co, Ni and Cu) doping on structural, optical and magnetic properties of ZnO nanostructures has been studied. Zn1−x TMx O (TM=Co, Ni and Cu) nanostructures were prepared by a microwave assisted chemical route and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, transmission electron microscopy (TEM), Raman spectroscopy, UV-Vis and magnetization measurements. XRD and TEM analyses showed that the TM-doped ZnO nanostructures had single phase nature with the wurtzite structure. Changes in the lattice volume, bandgap energy, morphology and the saturation magnetization of Zn1−x TMx O nanostructures were found to be dependent on the type of TM dopants. Lattice volume, bondlength and bandgap determined from XRD and UV-Vis, respectively, were found to decrease as the atomic number of the dopant increased from Co to Cu. Magnetic studies showed that all the TM-doped ZnO exhibited room temperature ferromagnetism and the decreasing trend of saturation magnetization was observed with the increase of 3d electrons number from Co to Cu.
    Journal- Korean Physical Society 05/2013; 62(10). · 0.43 Impact Factor