![]() ![]() The flux quantum is a natural constant with a value of h/2e (h Planck´s constant, e elementary charge of electron). ![]() The magnetic field can only quantized enter into or escape from the loop at a weak link of the structure (Josephson contact) and when it is changed. The external field generates a shielding current. By this, the so-called length of coherence is essentially determined which cannot be longer than a few µm, depending on the material.Īn external subcritical magnetic field cannot enter a closed superconducting structure, e.g. Thus they populate a single state on the Fermigrenze.Įlectron-phonon-interaction has a limited range. These pairs do not follow the Fermi-statistic, but they follow the Bose-statistic. ![]() 1 Our achievements are shown below in a simple way:īelow a low temperature, the so-called critical temperature, solid electrons in the surroundings of the Fermigrenze condense to pairs of electrons because of the (virtual) electron-phonon-interaction. Within half a year, we had learnt the most important features of physics of superconductivity. The result of our work was the “Josephson-Bibel” that was available to almost every member of our division. This led us from the minimization of the detectors´ noise for operating in low temperature over superconducting bolometers and irradiated Josephson contacts (Shortly before, the Josephson effect had been discovered.) to Superconducting Quantum Interference Devices (SQUIDs), which were initially scratched under the microscope.Īt that time, we did not have previous knowledge of physics of superconductivity, low temperature technics and, particularly not, the liquid helium but the colleagues from Dresden, who worked in the field of low temperature physics at the Academy of Sciences (AdW) under the responsibility of Ludwig Bewilogua, helped us.įirst, it was necessary to collect the accumulated experimental and theoretical knowledge and to process this knowledge for our purposes. Therefore, we initially searched for scientifically challenging problems which were of interest to toolbuilding and which had not been worked with by other groups of the nation. ![]() It was naturally based on the expectation of a demand from the nationally owned enterprise (VEB) Carl Zeiss Jena in reference to novel detectors in the field of optics. The former section "Physics for Scientific Toolbuilding" of Friedrich Schiller University (FSU), Jena (since 1971 Section of Physics) was founded in 1968 together with a division for Detector Physics (DP). ![]()
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