The feasibility of a proposed superconducting neuristor realization

The neuristor has been the subject of much experimental work, but no completely successful realization has yet emerged. In this paper a line is examined based on the motion of a normal region in a superconducting film superimposed on a conducting film. The current distribution near a moving normal/superconducting boundary is discussed and three operating modes are defined as functions of the displacement velocity. For two modes this velocity is greater than 10⁴m/s for a 10^-7m film, increasing with thickness. These velocities are unsuitable for present day technology, so further discussion is limited to the lower velocity mode. It is shown that even in this velocity range it is possible for the current in the normal region to exhibit the asymmetrical distribution necessary for device operation. It is then shown that the thermal relaxation times are sufficiently short for the temperature distribution to follow changes in the pattern of Joule heat generation, and hence show the asymmetries of the current patterns. Discussion of the resultant temperature distribution shows that the thermal conductivity of the superconductor is likely to be too large by many orders of magnitude, so satisfactory operation cannot be achieved. Suitable thermal conductivities can be deduced, but are unlikely to be achieved with available materials.