Superlattice Nanowires

1995 ◽  
Vol 384 ◽  
Author(s):  
K. Attenborough ◽  
R. Hart ◽  
W. Schwarzacher ◽  
J-PH. Ansermet ◽  
A. Blondel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Giant Magnetoresistance ◽  
Layer Structure ◽  
Interlayer Coupling ◽  
Nanoporous Membranes ◽  
Transmission Electron ◽  
Plane Anisotropy ◽  
Nonmagnetic Layer ◽  
Magnetostatic Coupling

ABSTRACTCoNiCu/Cu superlattice nanowires have been grown by electrodeposition in nuclear tracketched nanoporous membranes. Transmission electron microscopy (TEM) images show a good layer structure and allow an estimate of the current efficiency. Current perpendicular to plane (CPP) giant magnetoresistance of up to 22%, at ambient temperature, has been measured but appears to be limited by defects, giving rise to ferromagnetic interlayer coupling, at low nonmagnetic layer thicknesses. Magnetic properties of the superlattice nanowires are influenced by in-plane anisotropy and magnetostatic coupling.

scholarly journals Function of blue iridescence in tropical understorey plants

2010 ◽  
Vol 7 (53) ◽  
pp. 1699-1707 ◽  
Author(s):  
Katherine R. Thomas ◽  
Mathias Kolle ◽  
Heather M. Whitney ◽  
Beverley J. Glover ◽  
Ullrich Steiner
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Optical Properties ◽  
Lamellar Structure ◽  
Layer Structure ◽  
Green Leaves ◽  
Transmission Electron ◽  
Layer Structures ◽  
Understorey Plants ◽  
Light Capture

The blue colouration seen in the leaves of Selaginella willdenowii is shown to be iridescent. Transmission electron microscopy studies confirm the presence of a layered lamellar structure of the upper cuticle of iridescent leaves. Modelling of these multi-layer structures suggests that they are responsible for the blue iridescence, confirming the link between the observed lamellae and the recorded optical properties. Comparison of blue and green leaves from the same plant indicates that the loss of the blue iridescence corresponds to a loss of the multi-layer structure. The results reported here do not support the idea that iridescence in plants acts to enhance light capture of photosynthetically important wavelengths. The reflectance of light in the range 600–700 nm is very similar for both iridescent and non-iridescent leaves. However, owing to the occurrence of blue colouration in a wide variety of shade dwelling plants it is probable that this iridescence has some adaptive benefit. Possible adaptive advantages of the blue iridescence in these plants are discussed.

In-situ TEM studies of magnetization reversal processes in magnetic nanostructures

2005 ◽  
Vol 907 ◽  
Author(s):  
Amanda K Petford-Long ◽  
Thomas Bromwich ◽  
Amit Kohn ◽  
Victoria Jackson ◽  
Takeshi Kasama ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetization Reversal ◽  
Giant Magnetoresistance ◽  
Magnetic Nanostructures ◽  
Magnetic Domain ◽  
Ferromagnetic Material ◽  
In Situ Tem ◽  
Transmission Electron

AbstractOne of the most widely studied types of magnetic nanostructure is that used in devices based on the giant magnetoresistance (GMR) or tunnel magnetoresistance (TMR) phenomena. In order to understand the behaviour of these materials it is important to be able to follow their magnetisation reversal mechanism, and one of the techniques enabling micromagnetic studies at the sub-micron scale is transmission electron microscopy. Two techniques can be used: Lorentz transmission electron microscopy and off-axis electron holography, both of which allow the magnetic domain structure of a ferromagnetic material to be investigated dynamically in real-time with a resolution of a few nanometres. These techniques have been used in combination with in situ magnetizing experiments, to carry out qualitative and quantitative studies of magnetization reversal in a range of materials including spin-tunnel junctions, patterned thin film elements and magnetic antidot arrays. Quantitative analysis of the Lorentz TEM data has been carried out using the transport of intensity equation (TIE) approach.

Structure of Al-Hf Films

1976 ◽  
Vol 34 ◽  
pp. 634-635
Author(s):  
P. J. Smith ◽  
J. K. Howard ◽  
W. K. Chu ◽  
R. F. Lever
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Silicon Wafer ◽  
Layer Structure ◽  
Nitrogen Atmosphere ◽  
Aluminum Layer ◽  
Transmission Electron ◽  
Before And After

The structure of Al-Hf thin films, before and after annealing, has been studied by transmission electron microscopy. A 7000-Å layer of aluminum was evaporated, at a pressure of 5 x 10-7 Torr, onto a silicon wafer that had 5000 Å of thermal SiO2 on top. Onto the aluminum layer, with no break in the vacuum, a 1700-Å. layer of hafnium and then a 1000-Å layer of aluminum were deposited. The resulting three-layer structure was used to determine how different atomic ratios of Al and Hf influence the phases formed.After 4 hr of annealing at 400 C in a dry nitrogen atmosphere, the upper part of the film was found to be composed of grains of Al3Hf (ZrAl3-type), about 700 Å in diameter (Fig. 1). The reaction appeared to be complete in the upper layer; none of the relatively large Al grains, 2000 Å in diameter, that had been present in the as-deposited sample were found.

scholarly journals The Effect of Stirring on the Morphology of Birnessite Nanoparticles

2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Marcos A. Cheney ◽  
Pradip K. Bhowmik ◽  
Shingo Moriuchi ◽  
Mario Villalobos ◽  
Shizhi Qian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layer Structure ◽  
Dendritic Morphology ◽  
X Ray Diffraction ◽  
Mechanical Stirring ◽  
Transmission Electron ◽  
Initial Stage ◽  
Structural Preferences ◽  
Size And Morphology

The effect of mechanical stirring on the morphology of hexagonal layer-structure birnessite nanoparticles produced from decomposition ofKMnO4in dilute aqueousH2SO4is investigated, with characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), andN2adsorption (BET). Mechanical stirring during an initial stage of synthesis is shown to produce black birnessite containing nanofibers, whereas granular particulates of brown birnessite are produced without stirring. This is the first reduction synthesis of black birnessite nanoparticles with dendritic morphology without any use of organic reductant, and suggests that a particular morphology can arise from structural preferences of Mn in acidic conditions rather than particular organic reactants. These results enlighten the possibility of synthesizing nanoparticles with controlled size and morphology.

Transmission Electron Microscopy of Mocvd Titanium Nitride Films

1994 ◽  
Vol 337 ◽  
Author(s):  
Toshio Itoh ◽  
Toyohiko J. Konno ◽  
Robert Sinclair ◽  
Ivo J.M.M. Raaijmakers ◽  
Bruce E. Roberts
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layer Structure ◽  
The Other ◽  
Grain Structure ◽  
Tin Films ◽  
Si Substrates ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Columnar Grain

ABSTRACTThe effect of substrate temperature and process pressure on microstructure of MOCVD-TiN films deposited on oxidized Si substrates are studied by transmission electron microscopy (TEM). It is found that microstructure of MOCVD-TiN films distinctly changes with these deposition parameters and that the resistivity of the films is uniquely related to the microstructure. Films with the lowest resistivity (< 500 μohm-cm) show a uniform semi-columnar grain structure. Films with the highest resistivity (> 10,000 μohm-cm) show a uniform equi-axed micrograin structure. The other films exhibit a bi-layer structure: one layer of semi-columnar grains and the other of equiaxed micrograins. The thickness ratio of these layers changes with the deposition conditions and the resistivity is a unique function of the thickness of the semi-columnar grain layer.

Synthesis and Microstructure of Antimony Oxide Nanorods

2002 ◽  
Vol 17 (7) ◽  
pp. 1698-1701 ◽  
Author(s):  
Zaoli Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layer Structure ◽  
Large Angle ◽  
Antimony Oxide ◽  
Growth Direction ◽  
Internal Standards ◽  
Transmission Electron ◽  
Oxide Nanorods ◽  
Periodic Layer

Antimony oxide nanorods were synthesized by the microemulsion method. The nanorods had diameter in the range of 507–175 nm and a length of up to several micrometers. The microstructure of the nanorods was examined by analytical transmission electron microscopy and high-resolution transmission electron microscopy (HRTEM). Large-angle tilt diffraction experiments on the normal nanorods (about 90 nm in diameter) showed that they have an orthorhombic structure. Combining the results of internal standards using the silicon single crystal, it could be concluded that the synthesized nanorod is Sb2O4. The common growth direction of the nanorods was along the long axis. HRTEM images showed it had a periodic layer structure, and some defects and a layer of amorphous on the nanorods surface were found. The formation mechanism of Sb2O4 nanorods is briefly discussed.

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