Tolerance analysis of the superconducting continuous-sheet memory

A simple tolerance analysis of the superconducting continuous-sheet memory predicts maximum tolerances, of ±14%, but higher tolerances have been measured. The analysis presented here considers the implications of some of the simplifying assumptions traditionally made. More detailed considerations can either increase or decrease the predicted tolerances. The justification of the usual current switching analysis is examined, and it is concluded that a maximum average energy-density switching criterion should be used but that critical current switching has the dubious though useful advantage of simplicity. Since calculated tolerances depend on the simplifications assumed, any conclusions regarding the ultimate feasibility of proposals for the continuous-sheet memory which are based on calculated tolerances are ill founded. There seems to be no fundamental reason why the measured operating tolerances cannot be increased beyond 14% if the fabrication processes and parameters governing them can be elucidated and controlled.