High-Resolution Lattice Images of Superconductors Observed at 4.2 K

1990 ◽  
Vol 48 (1) ◽  
pp. 16-17
Author(s):  
Hiroyuki Yoshida ◽  
Yasuhiro Yokota ◽  
Hatsujiro Hashimoto ◽  
Masashi Iwatsuki ◽  
Yoshiyasu Harada
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Oxide Superconductors ◽  
Atomic Structures ◽  
Cryo Electron Microscopy ◽  
Resolution Observation ◽  
Lattice Images ◽  
High Resolution Images

High resolution cryo electron microscopy has been applied to the observation of microstructures of A15-type and oxide superconductors. In order to study the relation between atomic structures and superconducting properties the atomic resolution observation at cryogenic temperatures seems to be important, especially for high Tc superconductors with perovskite structure whose coherent length along c axis is closed to the lattice spacings. High resolution lattice images were obtained using a superconducting cryo electron microscope JEM-2000 SCM operated at 160 KV. The microscope enable the specimen to keep at 4.2 K without thermal drift and vibration under ultra high vacuum. The magnetic field at the specimen position is 1.4 T when the electron microscope is operated at 160 kV.Figure 1 shows a high resolution image of the electropolished thin crystal of Nb3(A10.77Ge0.23) (Tc=19 K). In the both sides of the grain boundary the (100) lattice fringes with 0.52 nm spacing of the A15 structure are clearly resolved. The high resolution images obtained for Nb3Sn superconductors gave the bright dots at the position of Nb atom chains along 001 direction as confirmed by the image contrast calculation.

The High Resolution Scanning Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 316-317
Author(s):  
A. V. Crewe
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
High Vacuum ◽  
Scanning Transmission Electron Microscope ◽  
Ultra High Vacuum ◽  
Resolving Power ◽  
Imaging Characteristics ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Moment

The high resolution STEM is now a fact of life. I think that we have, in the last few years, demonstrated that this instrument is capable of the same resolving power as a CEM but is sufficiently different in its imaging characteristics to offer some real advantages.It seems possible to prove in a quite general way that only a field emission source can give adequate intensity for the highest resolution^ and at the moment this means operating at ultra high vacuum levels. Our experience, however, is that neither the source nor the vacuum are difficult to manage and indeed are simpler than many other systems and substantially trouble-free.

High Resolution Lattice Images of G.P.Zones and Solute Clusters in Al-Cu and Cu-Be Alloys

1982 ◽  
Vol 21 ◽  
Author(s):  
H. Yoshida ◽  
H. Hashimoto ◽  
Y. Yokota ◽  
M. Takeda
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Atomic Structures ◽  
Resolution Electron ◽  
Microscope Images ◽  
Lattice Images ◽  
Lattice Planes

ABSTRACTAtomic structures of G.P. zones and solute clusters in Al-Cu and Cu-Be alloys are studied by the atom resolution electron microscope images. The images of plate-like G.P. zones appear as dotted images with various brightnesses along (200) lattice planes. The solute clusters are also observed along (111) lattice planes.

Objective-lens design for high resolution ultra high vacuum EM

1992 ◽  
Vol 50 (1) ◽  
pp. 292-293
Author(s):  
Arno J. Bleeker ◽  
J. Murray Gibson
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Free Space ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Objective Lens ◽  
Auxiliary Equipment ◽  
Physical Experiments ◽  
Under Construction ◽  
The University

Although the main use for Transmission electron microscopy is to study bulk phenomena it is also possible to do surface sensitive experiments with this type of instrument. In order to do reliable surface physical experiments it is necessary to improve the vacuum within the vicinity of the specimen to the Ultra High Vacuum (UHV) level. A number of authors report on such improvements. In most designs the experiments with the sample such as deposition and oxidation are done outside the main microscope column. This means that it is not possible to observe the sample under high resolution conditions during these experiments. The importance of the electron microscope as a surface sensitive instrument can be greatly enhanced if it would be possible to do surface physical experiments in-situ. In that way it would become possible to observe the specimen with high resolution during all kinds of surface processes. In order to be able to do these experiments there must exist a large free space around the sample. In this free space auxiliary equipment such as ion guns and MBE cells can be placed. To further enhance the capabilities of the instrument, analyzing tools such as an Auger spectrometer and SIMS equipment can be attached to the microscope. At the University of Illinois an electron microscope capable of imaging the sample during surface physical experiments is presently under construction. In this machine the objective lens section has been replaced by a large (800 mm diameter and 400 mm high) UHV chamber. The specimen is outside the magnetic field of the objective lens in order to obtain as much free space around the sample as possible thus sacrificing resolution.

UHV conversion of a 300 kV high-resolution electron microscope

1987 ◽  
Vol 45 ◽  
pp. 136-137
Author(s):  
Peter R. Swann ◽  
Joseph S. Jones ◽  
Ondrei L. Krivanek ◽  
David J. Smith ◽  
John A. Venables ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Full Range ◽  
High Vacuum ◽  
High Resolution Electron Microscopy ◽  
Ultra High Vacuum ◽  
Objective Lens ◽  
Surface And Interface ◽  
Resolution Electron ◽  
Point To Point

Ultra-high-vacuum high-resolution electron microscopy (UHV-HREM) is a powerful technique for studying the structure of surfaces, and for characterizing the mechanisms and kinetics of surface and interface reactions. It requires an electron microscope capable of atomic resolution, a vacuum of about 10-10 torr around the sample, and a range of specimen treatment capabilities. We have replaced the standard specimen chamber of a Philips 430ST high resolution microscope by a special UHV chamber which allows for limited specimen treatment in-situ, and a full range of specimen treatments in a preparation chamber mounted on the side of the microscope column. At 300 kV, the objective lens (Cs= Cc = 1.1mm) of the 430ST has demonstrated a point-to-point resolution of 2.0 Å, and a spatial frequency transfer limit with axial illumination of better than 1.5 Å. A critical specification for the microscope conversion was that this performance should not be compromised even under full UHV operation.

Surface Studies of Silicon with a High Resolution Transmission Electron Microscope

1985 ◽  
Vol 56 ◽  
Author(s):  
J.M. Gibson ◽  
M.L. McDonald ◽  
F.C. Unterwald ◽  
H.-J. Gossmann ◽  
J.C. Bean ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Bond Density ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Energy Surfaces

AbstractUsing a specially modified ultra-high vacuum, ultra-high resolution transmission electron microscope, in-situ cleaned Si surfaces have been examined with near atomic resolution. By annealing the edges of a <110> thin Si specimen in-situ, it is found that low energy surfaces form. A surprising observation is that the {113} surface is stable and reconstructed by dimerization to a very low dangling bond density. It is also found that a 7×7 surface peridoicity can be preserved at a buried Si < 111 > / amorphous Si interface.

Field Emission SEM Equipped With Noise Compensator

1973 ◽  
Vol 31 ◽  
pp. 302-303
Author(s):  
S. Saito ◽  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Contrast ◽  
Probe Current ◽  
High Resolution Images ◽  
Scanning Electron

Field emission scanning electron microscope (FESEM) features extremely high resolution images, and offers many valuable information. But, for a specimen which gives low contrast images, lateral stripes appear in images. These stripes are resulted from signal fluctuations caused by probe current noises. In order to obtain good images without stripes, the fluctuations should be less than 1%, especially for low contrast images. For this purpose, the authors realized a noise compensator, and applied this to the FESEM.Fig. 1 shows an outline of FESEM equipped with a noise compensator. Two apertures are provided gust under the field emission gun.

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