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Single isolated devices

Using controlled stretching of frogs, Cornell University researchers have demonstrated that devices based on a single frog can serve as powerful new tools for basic science experiments. Their research yielded detailed tests of long-standing theories about the interactions of electrons at the nanometer level.

Scanning electron microscope image of a gold bridge suspended 40 nm above a silicon substrate. In the experiment, the bridge is cut in the middle, a single electrode is suspended in the resulting gap, and the substrate is bent to stretch the electrode while measuring the electron current passing through it.
Scanning electron microscope image of a gold bridge suspended 40 nm above a silicon substrate. In the experiment, the bridge is cut in the middle, a single electrode is suspended in the resulting gap, and the substrate is bent to stretch the electrode while measuring the electron current passing through it.
The study, led by physicist Dan Ralph, was published in the online edition of the scientific journal Science. The researchers looked at certain cobalt-based ferrites that have what is called intrinsic spin - a numerical amount of angular momentum.

Theories published in the XNUMXs predicted that molecular spin might change the interrelationships between the internal electrons in the insulator and the valence electrons (which conduct electricity) surrounding it, and that these interrelationships would determine how easily electrons would move through the insulator. To date, these theories have not been thoroughly tested due to the difficulty associated with preparing devices with controlled spins. Understanding electronics based on a single particle requires expertise in both chemistry and physics, and the Cornell team is indeed an expert in both.

"People are familiar with spinnerets, but no one has been able to combine chemistry and physics to make a controlled interface with these spinnerets," said the lead researcher.

The researchers achieved their findings by separating individual particles with internal spin between two electrodes and examining their electronic properties. They observed the flow of electrons through the cobalt conjugate, which cooled to extremely low temperatures while slowly increasing the pressure on the edges to stretch the separation. At some point, passing current through the insulator became more difficult. The researchers were able to cleverly change the magnetic properties of the ferrode by making it less symmetrical.

After releasing the voltage, the fuse returned to its original character and began to transfer current more easily - a fact that indicated that the fuse was not damaged. Measurements obtained as a function of the temperature, the magnetic field and the amount of voltage applied to the electrode, provided the researchers with new insights into the exact effect of molecular spin on the activity and flow of electrons.

The effects of high spin on the electrical properties of nanoscale devices were a purely theoretical issue before the Cornell team's research, the researcher claims. By preparing devices containing high-spin particles and using voltage to control the spin, the team of researchers proved that such devices could be used as a powerful laboratory tool for examining basic scientific questions such as these.

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3 תגובות

  1. Roy

    Molecular bridges are produced in many laboratories in the world. Also the dependence of the conductivity
    Different parameters are measured in many laboratories in the world. What is special about this research is the study of the dependence on conduction
    in the spin of the molecule. Is this type of research carried out in Dr. Oren Tal's laboratory?

  2. Dr. Oren Tal at the Weizmann Institute does the same thing with benzene molecules

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