Transition to Ohmic conduction in microscopic tunnel junctions at low temperatures

1992 ◽  
Vol 45 (11) ◽  
pp. 6069-6073 ◽  
Author(s):  
R. Brown ◽  
E. Šima´nek
Keyword(s):  
Low Temperatures ◽  
Tunnel Junctions ◽  
Ohmic Conduction

scholarly journals Non-ohmic conduction in doped polyacetylene at low temperatures

1986 ◽  
Vol 64 (1) ◽  
pp. 19-23 ◽  
Author(s):  
H. Chaabane ◽  
E. Ettlinger ◽  
W. Schoepe
Keyword(s):  
Low Temperatures ◽  
Ohmic Conduction

Quantum-dot Cellular Automata

2001 ◽  
Vol 696 ◽  
Author(s):  
Gregory L. Snider ◽  
Alexei O. Orlov ◽  
Ravi K. Kummamuru ◽  
Rajagopal Ramasubramaniam ◽  
Islamshah Amlani ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cellular Automata ◽  
Quantum Dot ◽  
Low Temperatures ◽  
Tunnel Junctions ◽  
Operating Temperature ◽  
Building Blocks ◽  
Quantum Dot Cellular Automata ◽  
Background Charge ◽  
Metal Islands

AbstractAn overview is given of the quantum-dot cellular automata (QCA) architecture, along with a summary of experimental demonstrations of QCA devices. QCA is a transistorless computation paradigm that can provide a solution to such challenging issues as device and power density. The basic building blocks of the QCA architecture, such as AND, OR gates and clocked cells have been demonstrated and will be presented here. The quantum dots used in the experiments to date are metal islands that are coupled by capacitors and tunnel junctions, and devices operate only at very low temperatures. For QCA to be used in practical devices, the operating temperature must be raised, and issues such as background charge must be addressed. An introduction will be given to these issues and possible solutions.

Noise anomalies in small tunnel junctions at low temperatures

1987 ◽  
Vol 126 (3) ◽  
pp. 201-204 ◽  
Author(s):  
Yu.A. Genenko ◽  
Yu.M. Ivanchenko
Keyword(s):  
Low Temperatures ◽  
Tunnel Junctions

Anomalous Behavior in Spin Dependent Tunnel Junctions

1997 ◽  
Vol 475 ◽  
Author(s):  
C. L. Platt ◽  
B. Dieny ◽  
A.E. Berkowitz
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Barrier Layer ◽  
Tunnel Junction ◽  
Applied Magnetic Field ◽  
Low Temperatures ◽  
Tunnel Junctions ◽  
Anomalous Behavior ◽  
Field Transition

ABSTRACTSpin dependent tunneling has been investigated in tunnel junctions composed of a variety of materials. The best results thus far have been with either HfO2 or MgO as the barrier layer using CoFe, Fe, or Co as the magnetic electrodes. The maximum magnetoresistive (MR) response of these junctions has been at low temperatures on the order of 30% in HfO2 and 20% in MgO. We have also observed a variety of anomalous behavior in some of our tunnel junctions at low temperature. These include MR effects dependent on the angle of orientation of the tunnel junction in the applied magnetic field, transition fields greater than lOkOe, and negative MR effects on the order of 2%.

Transition to Ohmic conduction in ultrasmall tunnel junctions

1986 ◽  
Vol 34 (4) ◽  
pp. 2957-2959 ◽  
Author(s):  
R. Brown ◽  
E. Šimánek
Keyword(s):  
Tunnel Junctions ◽  
Ohmic Conduction

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

Radiation Damage of Support Films

1981 ◽  
Vol 39 ◽  
pp. 28-29
Author(s):  
H.A. Cohen ◽  
W. Chiu
Keyword(s):  
Transfer Function ◽  
Low Temperatures ◽  
Carbon Support ◽  
Contrast Transfer Function ◽  
Electron Dose ◽  
Imaging Parameters ◽  
Negative Stain ◽  
Phase Corrections ◽  
Two Parameters ◽  
Medium Dose

The goal of imaging the finest detail possible in biological specimens leads to contradictory requirements for the choice of an electron dose. The dose should be as low as possible to minimize object damage, yet as high as possible to optimize image statistics. For specimens that are protected by low temperatures or for which the low resolution associated with negative stain is acceptable, the first condition may be partially relaxed, allowing the use of (for example) 6 to 10 e/Å2. However, this medium dose is marginal for obtaining the contrast transfer function (CTF) of the microscope, which is necessary to allow phase corrections to the image. We have explored two parameters that affect the CTF under medium dose conditions.Figure 1 displays the CTF for carbon (C, row 1) and triafol plus carbon (T+C, row 2). For any column, the images to which the CTF correspond were from a carbon covered hole (C) and the adjacent triafol plus carbon support film (T+C), both recorded on the same micrograph; therefore the imaging parameters of defocus, illumination angle, and electron statistics were identical.

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

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