Nanometer-area diffraction of small iron crystallites in single crystalline Fe-MgO composite films

1988 ◽  
Vol 46 ◽  
pp. 706-707
Author(s):  
N. Tanaka ◽  
K. Mihama ◽  
H. Ou ◽  
J.M. Cowley
Keyword(s):  
Phase Transformation ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Carbon Film ◽  
Composite Films ◽  
High Resolution Electron Microscopy ◽  
Scanning Transmission Electron Microscope ◽  
Specimen Preparation ◽  
Single Crystalline ◽  
Transmission Electron

Nanometer-sized iron(Fe) crystallites can be prepared in a single crystalline magnesium oxide(MgO) film by a simultaneous vacuum deposition of Fe and MgO. The crystallites are grown epitaxially and almost coherently in the film, the orientation being (001) [110]Fe//(001)[100]MgOand (011) [100]Fe//(001) [100]MgO. A heat treatment of the as-grown composite films at 500-1000°C brings about a phase-transformation from α -iron(b.c.c.) to γ -iron(f.c.c.). In the present study, the phase-transformation and the structure of the γ-iron crystallites are studied by nanometer-area electron diffraction(nanodiffraction) in TEM and STEM as well as high-resolution electron microscopy.The specimens were single crystalline Fe-MgO composite films prepared on a NaCl (001 ) surface by co-evaporation of Fe and MgO. The films were separated from the substrate in water and mounted on a perforated carbon film. Nanodiffraction in TEM was performed in a 200 kV transmission electron microscope(JEM- 2000FX)2 and that in STEM3was carried out in a 100 kV scanning transmission electron microscope (VG-HB5) equipped with a specimen-preparation chamber.

Transmission Electron Microscopy study of lead sulfide whiskers

1989 ◽  
Vol 47 ◽  
pp. 444-445
Author(s):  
S.A. Mansour ◽  
R. Scholz
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Lead Sulfide ◽  
Carbon Film ◽  
Flame Temperature ◽  
High Resolution Electron Microscopy ◽  
Spiral Coil ◽  
Transmission Electron

This paper describes a transmission electron microscopy (TEM) study of the structure and growth mechanism of lead sulfide (PbS) whiskers. PbS whiskers were grown inside the stainless steel nozzle of a kerosene burner. The nozzle had a 0.5 mm aperture, and was fitted with an Al-spiral coil to filter kerosene impurities. The burner was operated continuously for four weeks at a kerosene pressure of 2-3 bars and a flame temperature of about 350°C before the nozzle clogged. A thick black deposit of fine PbS whiskers was found inside the nozzle.TEM specimens were prepared by ultrasonically suspending the fine black powder in alcohol. The suspended particles were deposited on a perforated carbon film supported on a copper grid, and examined with a JEM-1200EX transmission electron microscope operated at 120kV accelerating voltage. A JEM-4000EX transmission electron microscope was used for high resolution electron microscopy.Fig. 1. shows an EM micrograph of typical PbS whiskers. Each appears to have a high-contrast core encapsulated in a lower contrast shell. The electron diffraction pattern of a single whisker protruding over a hole in the carbon film is shown in Fig. 2.

Cutting of 20 Å holes and lines in metal-β-aluminas

1983 ◽  
Vol 41 ◽  
pp. 100-101 ◽  
Author(s):  
M.E. Mochel ◽  
C. J. Humphreys ◽  
J. M. Mochel ◽  
J. A. Eades
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Carbon Film ◽  
Scanning Transmission Electron Microscope ◽  
High Electron ◽  
Transmission Electron ◽  
Solid Substrates ◽  
Scanning Transmission ◽  
Very High

Holes 20 Å in diameter and fine lines 20 Å wide can be cut in the metal-β-aluminas using the 10 Å electron beam of the Vacuum Generators, HB5 scanning transmission electron microscope. The minimum current density required for cutting was 103 amp/cm2. Electron energies of 40,60,80,100 keV were used.This technique has higher resolution than current lithography methods and is direct, requiring no chemical development. The width of isolated lines made on solid substrates is currently about .1μm (Ahmed and McMahon, 1981) and .03μm (Jackel et al., 1980). M. Isaacson and A. Murry have carried out electron beam writing on NaCl crystals supported on a carbon film on the scale we report here.In our case uniform 20Å holes and lines can be cut through self-supporting 1000A thick slabs of sodium-β-alumina to provide very high electron contrast. Once cut, the β-aluminas are stable and will tolerate exposure to air without degradation of the electron cut patterns. They may be used directly as masks (eg. for ion implantation). We believe they could be cut on the substrate with no damage to the underlying material.

Electron Beam-Induced Nano-Deposition Using a Transmission Electron Microscope

2005 ◽  
Vol 480-481 ◽  
pp. 129-132 ◽  
Author(s):  
Masayuki Shimojo ◽  
Kazutaka Mitsuishi ◽  
M. Tanaka ◽  
M. Song ◽  
Kazuo Furuya
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
High Resolution Electron Microscopy ◽  
Scanning Transmission Electron Microscope ◽  
Beam Position ◽  
Nano Crystalline ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Scanning Transmission

Nanometre-sized structures were fabricated by electron beam-induced deposition in a scanning transmission electron microscope. A small amount of metal-organic gases, W(CO)6 and dimethyl acetylacetonato gold, were introduced near a substrate in the chamber of the microscope. The gas was decomposed by the irradiation of focused electron beams and nanometre-sized deposits containing W or Au were produced. Moving the beam position enables us to produce structures with a variety of shapes. High-resolution electron microscopy observation revealed that the structures consisted of nano-crystalline and amorphous parts.

The direct determination of magnetic domain wall profiles using a split detector STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 466-467
Author(s):  
J.N. Chapman ◽  
P.E. Batson ◽  
E.M. Waddell ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Domain Wall ◽  
Transmission Electron Microscope ◽  
Domain Walls ◽  
Photographic Plate ◽  
Magnetic Domain ◽  
Direct Determination ◽  
Quantitative Information ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.

A General Method for Spectrometer Design in the Scoff Approximation

1976 ◽  
Vol 34 ◽  
pp. 538-539
Author(s):  
J. R. Fields
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Energy Analysis ◽  
Incident Beam ◽  
Scanning Transmission Electron Microscope ◽  
Chemical Identification ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
General Method

The energy analysis of electrons scattered by a specimen in a scanning transmission electron microscope can improve contrast as well as aid in chemical identification. In so far as energy analysis is useful, one would like to be able to design a spectrometer which is tailored to his particular needs. In our own case, we require a spectrometer which will accept a parallel incident beam and which will focus the electrons in both the median and perpendicular planes. In addition, since we intend to follow the spectrometer by a detector array rather than a single energy selecting slit, we need as great a dispersion as possible. Therefore, we would like to follow our spectrometer by a magnifying lens. Consequently, the line along which electrons of varying energy are dispersed must be normal to the direction of the central ray at the spectrometer exit.

Resolution in the Scanning Transmission Electron Microscope

1972 ◽  
Vol 30 ◽  
pp. 454-455
Author(s):  
M. G. R. Thomson
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Spherical Aberration ◽  
Signal To Noise Ratio ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Objective Lens ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The variation of contrast and signal to noise ratio with change in detector solid angle in the high resolution scanning transmission electron microscope was discussed in an earlier paper. In that paper the conclusions were that the most favourable conditions for the imaging of isolated single heavy atoms were, using the notation in figure 1, either bright field phase contrast with β0⋍0.5 α0, or dark field with an annular detector subtending an angle between ao and effectively π/2.The microscope is represented simply by the model illustrated in figure 1, and the objective lens is characterised by its coefficient of spherical aberration Cs. All the results for the Scanning Transmission Electron Microscope (STEM) may with care be applied to the Conventional Electron Microscope (CEM). The object atom is represented as detailed in reference 2, except that ϕ(θ) is taken to be the constant ϕ(0) to simplify the integration. This is reasonable for θ ≤ 0.1 θ0, where 60 is the screening angle.

Measurement of lattice parameter at the nanometer scale using convergent-beam microdiffraction from a thermal emission source

1993 ◽  
Vol 51 ◽  
pp. 690-691
Author(s):  
W. T. Pike
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Thermal Emission ◽  
Lattice Parameter ◽  
Scanning Transmission Electron Microscope ◽  
Emission Source ◽  
Device Structure ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Convergent Beam

With the advent of crystal growth techniques which enable device structure control at the atomic level has arrived a need to determine the crystal structure at a commensurate scale. In particular, in epitaxial lattice mismatched multilayers, it is of prime importance to know the lattice parameter, and hence strain, in individual layers in order to explain the novel electronic behavior of such structures. In this work higher order Laue zone (holz) lines in the convergent beam microdiffraction patterns from a thermal emission transmission electron microscope (TEM) have been used to measure lattice parameters to an accuracy of a few parts in a thousand from nanometer areas of material.Although the use of CBM to measure strain using a dedicated field emission scanning transmission electron microscope has already been demonstrated, the recording of the diffraction pattern at the required resolution involves specialized instrumentation. In this work, a Topcon 002B TEM with a thermal emission source with condenser-objective (CO) electron optics is used.

Development of Line Analysis and Real-Time Elemental Mapping System in Stem Equipped with a Two-Window Energy Filter

2001 ◽  
Vol 7 (S2) ◽  
pp. 1134-1135
Author(s):  
K. Kaji ◽  
T. Aoyama ◽  
S. Taya ◽  
S. Isakozawa
Keyword(s):  
Electron Microscope ◽  
Energy Loss ◽  
Transmission Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
Elemental Mapping ◽  
Additional Function ◽  
Edge Structure ◽  
Transmission Electron ◽  
Mapping System ◽  
Scanning Transmission

The ability to obtain elemental maps processed by using inelastically scattered electrons in a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM) is extremely useful in the analysis of materials, and semiconductor devices such as ULSI’s and GMR heads. Electron energy loss spectra (EELS) also give useful information not only to identify unknown materials but also to study chemical bonding states of the objective atoms. Hitachi developed an elemental mapping system, consisting of a STEM (Hitachi, HD- 2000) equipped with a two-window energy filter (Hitachi, ELV-2000), and performed realtime conventional jump-ratio images with nanometer resolution by in-situ calculation of energy-filtered signals [1]. Additional function of acquiring EELS along any lines on specimen has been developed in this system to investigate the energy loss near edge structure (ELNES).Figure 1 shows a schematic figure of the two-window energy filter, consisting of two quadrupole lenses for focusing and zooming spectra, respectively, a magnetic prism spectrometer, a deflection coil and two kinds of electron beam detectors.

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