Single-Crystal Iron Nanowire Arrays

2007 ◽  
Vol 121-123 ◽  
pp. 17-20 ◽  
Author(s):  
Yue Ling Sun ◽  
Ying Dai ◽  
L.Q. Zhou ◽  
Wen Chen
Keyword(s):  
Electron Microscope ◽  
Single Crystal ◽  
Hysteresis Loops ◽  
Nanowire Arrays ◽  
X Ray Diffraction ◽  
Easy Magnetization ◽  
Transmission Electron ◽  
Iron Nanowires ◽  
Xrd Patterns ◽  
Different Diameters

Highly ordered single-crystal iron nanowire arrays with different diameters have been fabricated in anodic aluminum oxide (AAO) templates by DC electrodeposition method. The Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) show that the iron nanowires are highly uniform and exhibit a single crystal structure. The X-ray diffraction (XRD) patterns of iron nanowire arrays indicate that most of the iron nanowire arrays have the obvious preferred orientation along the [200] direction. From the hysteresis loops of the iron nanowires, it reveals that the easy magnetization axes of nanowire arrays are along the long axis. The sample with smaller diameter (d=35nm) has a high square ratio (up to 98%) and a high coercive filed (1265Oe) when the external magnetic field is applied along axis of the nanowires. When the diameter decreases, the square ratio and the coercive field increase due to the single-domain structure and the strong shape anisotropy in the smaller diameter nanowire arrays.

scholarly journals Temperature-Dependent Raman Scattering of Large Size Hexagonal Bi2Se3 Single-Crystal Nanoplates

2018 ◽  
Vol 8 (10) ◽  
pp. 1794 ◽  
Author(s):  
Fang Zhou ◽  
Yujing Zhao ◽  
Weichang Zhou ◽  
Dongsheng Tang
Keyword(s):  
Electron Microscope ◽  
Single Crystal ◽  
Temperature Coefficient ◽  
Thermoelectric Materials ◽  
Large Scale ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Large Size ◽  
Transmission Electron ◽  
High Figure

Bi 2 Se 3 has extensive application as thermoelectric materials. Here, large-scale Bi 2 Se 3 single-crystal hexagonal nanoplates with size 7.50–10.0 μ m were synthesized successfully by hydrothermal method. X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize the Bi 2 Se 3 nanoplates, which confirm the single-crystal quality and smooth surface morphology with large size. Micro-Raman spectra over a temperature range of 83–603 K were furthermore used to investigate the lattice dynamics of Bi 2 Se 3 nanoplates. Both 2A g 1 and 1E g 2 modes shift evidently with reduced temperature. The line shape demonstrates a significant broadening of full width at half maximum (FWHM) and red-shift of frequency with increased temperature. The temperature coefficient of A 1 g 1 , E g 2 , A 1 g 2 modes were determined to be −1.258 × 10 − 2 cm − 1 /K, −1.385 × 10 − 2 cm − 1 /K, −2.363 × 10 − 2 cm − 1 /K, respectively. Such low temperature coefficient may favor the obtaining of a high figure of merit (ZT) and indicate that Bi 2 Se 3 nanoplates were used as excellent candidates of thermoelectric materials.

Improvement of the Crystallinity of La2CuO4 Nanoparticles Using the Vacuum Treatment

2021 ◽  
Vol 1028 ◽  
pp. 44-49
Author(s):  
Anita Eka Putri ◽  
Suci Winarsih ◽  
Budhy Kurniawan ◽  
Dicky Rezky Munazat ◽  
Dhawud Sabilur Razaq ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Vacuum Treatment ◽  
Vacuum Pressure ◽  
Morphological Properties ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Xrd Patterns

Nanoparticles of La2CuO4 (LCO) with different particles and crystallite size have been synthesized by the sol-gel method. The samples have been sintered at 600, 650, and 700°C. The sintering process have been performed in atmospheric pressure and vacuum pressure. The structural and morphological properties of the samples have been investigated by the X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM). The XRD patterns of the samples have shown that all samples crystallize in orthorhombic structure with Bmab space group. Additionally, Rietveld refinement process have shown that higher sintering temperature, as well sintering process under vacuum pressure, can improve both phase purity and the crystallinity of the samples. SEM and TEM results have also shown that higher sintering temperature results in a sample with larger particle size.

Preparation of Single-Crystal BiOCl Nanorods via Surfactant Soft-Template Inducing Growth

2005 ◽  
Vol 23 ◽  
pp. 79-82 ◽  
Author(s):  
Chuan Bao Cao ◽  
Ruitao Lv ◽  
He Sun Zhu
Keyword(s):  
Electron Microscope ◽  
Single Crystal ◽  
Saed Pattern ◽  
Soft Template ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Triton X

Nanorods of a compound semiconductor, BiOCl, have been prepared from BiCl3 solutions containing a nonionic surfactant, t-octyl-(OCH2CH2)xOH, x=9, 10 (Triton X-100). Powder X-ray diffraction (XRD) pattern indicated that the product was pure tetragonal phase bismoclite (BiOCl). The product was also characterized by the techniques of scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and transmission electron microscope (TEM). The as-obtained BiOCl nanorods possess mean diameters less than 40nm and lengths ranging in 160-400nm. Selected area electron diffraction (SAED) pattern showed the single-crystal nature of as-prepared BiOCl nanorods. The growth mechanism of BiOCl nanorods has also been proposed.

Crystallographic and Magnetic Properties of CoCrPt Thin Films Investigated Using Single-Crystal Perpendicular Magnetic Thin Film Samples

2002 ◽  
Vol 721 ◽  
Author(s):  
Masaaki Futamoto ◽  
Kouta Terayama ◽  
Katsuaki Sato ◽  
Nobuyuki Inaba ◽  
Yoshiyuki Hirayama
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetic Properties ◽  
Single Crystal ◽  
Film Plane ◽  
Magnetic Thin Film ◽  
X Ray Diffraction ◽  
Easy Magnetization ◽  
Transmission Electron ◽  
Magnetization Axis

AbstractConditions to prepare good single-crystal CoCrPt magnetic thin film with the easy magnetization axis perpendicular to the film plane were investigated using oxide single-crystal substrates, Al2O3(0001), LaAlO3(0001), mica(0001), SrTiO3(111), and MgO(111). The best CoCrPt(0001) single-crystal thin film was obtained on an Al2O3(0001) substrate employing a non-magnetic CoCrRu underlayer. The crystallographic quality of single-crystal thin film was investigated using X-ray diffraction and high-resolution transmission electron microscopy. Some intrinsic magnetic properties (Hk, Ku) were determined for the single-crystal CoCrxPty thin films for a compositional range of x=17-20at% and y=0-17at%.

THE ASSEMBLY OF CHAIN-LIKE Ni ARRAYS UNDER MAGNETIC FIELD AND ITS ENHANCED PROPERTIES

2010 ◽  
Vol 09 (05) ◽  
pp. 543-547 ◽  
Author(s):  
JUN WANG ◽  
SHIHE CAO ◽  
SIHUA XIA ◽  
NING GAN
Keyword(s):  
Magnetic Field ◽  
Electron Microscope ◽  
External Magnetic Field ◽  
Self Assembly ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
Vertical Arrays ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Facile Hydrothermal Process

Chain-like nickel arrays assembled from magnetic Ni spheres were successfully prepared through a facile hydrothermal process at 200°C under a 0.25 T external magnetic field. The external magnetic field is strongly believed to be the driving force of the self-assembly. The sample was highly crystalline as confirmed by the X-ray diffraction (XRD) patterns. The scanning electron microscope (SEM) and transmission electron microscope (TEM) images show that all Ni spheres are closely interconnected to form chains, with ~ 950 nm in diameter and ~ 1 cm in length, which arrange into vertical arrays on the silicon substrate. The coercivity and remnant magnetization ratio of the sample, 670 Oe and 0.612, respectively, are substantially higher than for the sample prepared without an applied external magnetic field (68 Oe and 0.336). Such enhancements can be attributed to their novel superstructure, shape anisotropy, reduced demagnetization factor, etc. This process can be used to fabricate large arrays of uniform chains of magnetic materials and modulate their magnetic properties.

Synthesis and Characterization of Monodisperse Magnetite Nanoparticles by Hydrothermal Method

2017 ◽  
Vol 737 ◽  
pp. 367-372
Author(s):  
Apichon Watcharenwong ◽  
Yotsapon Bailuang ◽  
Puangrat Kajitvichyanukul
Keyword(s):  
Electron Microscope ◽  
Saturation Magnetization ◽  
Hydrothermal Method ◽  
Magnetite Nanoparticles ◽  
Hysteresis Loops ◽  
Spherical Shape ◽  
Pollutant Removal ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Transmission Electron

Monodisperse nanoparticles are materials that are not agglomerate. The good characteristic of these materials is the dispersity in water, so they can better react with target pollutants. Accordingly, in this work, the monodisperse magnetite nanoparticles with the superparamagnetic property were synthesized and characterized. The hydrothermal method with the iron compound and polymer as precursors was conducted. The magnetic nanoparticles were characterized by several techniques including X-ray diffraction, field emission scanning electron microscope, transmission electron microscope, and vibrating sample magnetometer. The saturation magnetization (Ms) value, the coercivity (Hc), and the retentivity (Mr) were measured to demonstrate the paramagnetic behavior of the monodisperse magnetite nanoparticles. The results showed that the Fe3O4 nanoparticle were obtained at 200 °C for 16 h. The particles are monodispersed with the size approximately in the range of 60 - 250 nm as confirmed by FE-SEM and TEM images. These are the single grain and had the spherical shape similar to a blackberry. The saturation magnetization of 17.287 emu/g and ratio of retentivity to saturation magnetization (Mr/Ms) characterized the squareness of the hysteresis loops was 0.03653. It can be indicated that the Fe3O4 nanoparticles had superparamagnetic behavior. This property of Fe3O4 nanoparticles can draw pollutants to absorb on the surface of these nanomaterials. Then adsorbed pollutants can be easily removed by separating the Fe3O4 materials from water. This technique can be applied further in water treatment and pollutant removal.

ARC Discharge for the Synthesis of Monoclinic Ga2O3 Nanowires

1999 ◽  
Vol 581 ◽  
Author(s):  
Young Chul Choi ◽  
Dong Jae Bae ◽  
Seung Mi Lee ◽  
Young Soo Park ◽  
Young Hee Lee ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Arc Discharge ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Crystalline Nature ◽  
Twin Defects ◽  
Xrd Patterns ◽  
Gallium Oxides ◽  
Ft Raman

ABSTRACTMonoclinic gallium oxide (β-Ga2O3) nanowires were catalytically synthesized by electric arc discharge of GaN powders mixed with a small amount (less than 5 %) of transition metals under a pressure of 500 Torr (80 %-Ar + 20 %-O2). Scanning electron microscope (SEM) and high-resolution transmission electron microscope (HRTEM) images showed that the average diameter of the wires were about 30 nm and their lengths were as long as up to one hundred micrometer, resulting in extremely large aspect ratio. Fourier diffractogram was indicative of single crystalline nature of the β-Ga2O3 wire. HRTEM image also showed β-Ga2O3 with twin defects at the center of the wire which might play as nucleation seeds. Both X-ray diffraction (XRD) patterns and FT-Raman spectra of the wires identified the observed nanowires as monoclinic crystalline gallium oxides.

Synthesis and Magnetic Characterization of Nickel Ferrite Nanowire Arrays Doped with Manganese

2011 ◽  
Vol 233-235 ◽  
pp. 1799-1802 ◽  
Author(s):  
Jian Jun Gu ◽  
Li Hu Liu ◽  
Yun Kai Qi ◽  
Qin Xu ◽  
Hui Yuan Sun
Keyword(s):  
Nickel Ferrite ◽  
Magnetic Measurements ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Average Diameter ◽  
Nanowire Arrays ◽  
X Ray Diffraction ◽  
Easy Magnetization ◽  
Magnetization Direction ◽  
Transmission Electron

The spinel ferrite system Ni1-xMnxFe2O4 (x = 0.0, 0.25, 0.5, 0.75) nanowire arrays with an average diameter of about 80 nm, have been synthesized into nanopores of anodic aluminum oxide (AAO) template using the sol–gel technique. X-ray diffraction analysis shows the formation of single-phase nickel manganese ferrites. Scanning electron microscopy and transmission electron microscope images indicate that the nanowire arrays are composed of prolate spheroids with different crystal orientations. Magnetic measurements show that the saturation magnetization (Ms) of nickel ferrite nanowire arrays is lower than that of bulk ones. But the Ms of the samples doped with Mn are greater than that of bulk ones. We do not observe obviously easy magnetization direction of all nanowire arrays. The possible reasons that are responsible for the composition dependence of the properties are discussed.

Highly Ordered and Well-oriented Single-crystal CdTe Nanowire Arrays by Direct-current Electrodeposition

2002 ◽  
Vol 17 (7) ◽  
pp. 1711-1714 ◽  
Author(s):  
Dongsheng Xu ◽  
Yuguo Guo ◽  
Dapeng Yu ◽  
Guolin Guo ◽  
Youqi Tang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
High Resolution Electron Microscopy ◽  
Growth Direction ◽  
Nanowire Arrays ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Anodic Aluminum Oxide Templates ◽  
Oriented Single Crystal

Highly ordered CdTe nanowire arrays were prepared by electrochemical deposition into the pores of anodic aluminum oxide templates from an ethylene glycol bath containing CdCl2, TeCl4, and KI. Electron microscopy results showed that the length, diameter, and direction of growth of the nanowires were quite uniform. X-ray diffraction, transmission electron microscopy, and high-resolution electron microscopy investigations showed that these nanowires had a crystalline structure of hexagonal CdTe single crystal with a uniform [001] growth direction.

Ti-doped Lithium Iron Phosphate (LiFePO4) Cathode Materials: Synthesis and Electrochemical Evaluation

2012 ◽  
Vol 15 (2) ◽  
pp. 63-69 ◽  
Author(s):  
Keqiang Ding ◽  
Wenjuan Li ◽  
Hongwei Yang ◽  
Suying Wei ◽  
Zhanhu Guo
Keyword(s):  
Electron Microscope ◽  
Lithium Iron Phosphate ◽  
Iron Phosphate ◽  
Cycling Performance ◽  
X Ray Diffraction ◽  
Materials Synthesis ◽  
Sem Images ◽  
Solid State Method ◽  
Transmission Electron ◽  
Xrd Patterns

The Ti doped LiFePO4 samples, i.e., LiFe1-xTixPO4 (X=0.01, 0.03 and 0.05), were prepared by a modified solid state method. The obtained samples were thoroughly characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). XRD patterns indicated that an olivine-type LiFePO4 was fabricated, and SEM images revealed that the particle size of LiFe0.99Ti0.01PO4 was the smallest among the obtained samples. The charge-discharge curves showed that LiFe0.99Ti0.01PO4 delivered the discharge capacity of 153.5 mAh/g at 0.2 C, the largest one among the as-prepared samples, which is rather different from the published report that LiFe0.97Ti0.03PO4 manifested the most promising cycling performance among the samples of LiFe1-xTixPO4 (X=0.01, 0.03, 0.05, 0.07 and 0.09).

Sign in / Sign up

Export Citation Format

Share Document